Liquid ejection device and control method for liquid ejection device

Abstract

The present invention provides a liquid ejection device and a control method for a liquid ejection device, which can reduce the possibility of the liquid ejection head sucking liquid from the nozzle. The liquid ejection device includes: a liquid ejection head (23) that ejects liquid from a nozzle (22) provided on a nozzle surface (21); a first storage unit (33) having an introduction unit (60) capable of introducing the liquid stored in a liquid storage unit (24) at an upper portion thereof, and a first liquid level (66) varying within a range lower than the nozzle surface (21); a second storage unit (35) communicating with the first storage unit (33) via a communication path (34) and supplied with liquid from the first storage unit (33) by a head difference; a supply flow path (37) that supplies liquid from the second storage unit (35) to the liquid ejection head (23); a pressurizing unit (47) that pressurizes the inside of the second storage unit (35); and a first valve (36) that can close the communication path (34) when pressurized by the pressurizing unit (47).

Description

Technical Field

[0001] The present invention relates to a liquid ejection device such as a printer. Background Art

[0002] For example, as shown in Patent Document 1, there is a recording device as an example of a liquid ejection device that ejects ink as an example of a liquid from nozzles formed on a recording head as an example of a liquid ejection head to perform printing. The recording device sucks ink from the nozzles by operating a suction pump in a state where a lid is in contact with the recording head.

[0003] Patent Document 1: Japanese Patent Laid-Open No. 2014-024189

[0004] Regarding suction cleaning for sucking and discharging a liquid, after the suction cleaning is completed, a negative pressure is also generated inside the liquid ejection head. Therefore, the recording head may suck the liquid attached to the nozzle surface where the nozzles are provided from the nozzles, causing the liquids to mix with each other inside the recording head. Summary of the Invention

[0005] A liquid ejection device for solving the above technical problems includes: a liquid ejection head that ejects a liquid from nozzles provided on a nozzle surface; a first storage unit having an introduction unit provided at an upper part, the introduction unit being capable of introducing the liquid stored in a liquid storage unit, and a liquid level of the first storage unit varying within a range lower than the nozzle surface; a second storage unit communicating with the first storage unit via a communication path, and the liquid being supplied from the first storage unit to the second storage unit by a water head difference; a supply flow path that supplies the liquid from the second storage unit to the liquid ejection head; a pressurizing unit that pressurizes the inside of the second storage unit; and a first valve that can close the communication path when pressurized by the pressurizing unit. Brief Description of the Drawings

[0006] Figure 1 is a perspective view of a first embodiment of a liquid ejection device.

[0007] Figure 2 is a schematic diagram of a supply mechanism and a drive mechanism included in the liquid ejection device of the first embodiment.

[0008] Figure 3 is a flowchart showing a liquid filling routine of the first embodiment.

[0009] Figure 4 is a flowchart showing a liquid circulation routine of the first embodiment.

[0010] Figure 5 is a flowchart showing a printing routine of the first embodiment.

[0011] Figure 6It is a flowchart showing the pressurized discharge routine of the first embodiment.

[0012] Figure 7 It is a flowchart showing the pressure accumulation discharge routine of the first embodiment.

[0013] Figure 8 It is a flowchart showing the micro-pressurized discharge routine of the first embodiment.

[0014] Figure 9 It is a flowchart showing the head replacement routine of the first embodiment.

[0015] Figure 10 It is a perspective view of the second embodiment of the liquid ejection device.

[0016] Figure 11 It is a schematic diagram of the supply mechanism and the drive mechanism included in the liquid ejection device of the second embodiment.

[0017] Figure 12 It is a flowchart showing the overall filling routine of the second embodiment.

[0018] Figure 13 It is a flowchart showing the liquid circulation routine of the second embodiment.

[0019] Figure 14 It is a flowchart showing the printing routine of the second embodiment.

[0020] Figure 15 It is a flowchart showing the pressurized discharge routine of the second embodiment.

[0021] Figure 16 It is a flowchart showing the pressure accumulation discharge routine of the second embodiment.

[0022] Figure 17 It is a flowchart showing the micro-pressurized discharge routine of the second embodiment.

[0023] Figure 18 It is a flowchart showing the head replacement routine of the second embodiment.

[0024] Explanation of reference numerals

[0025] 11…Liquid ejection device; 12…Medium; 13…Medium storage section; 14…Stacker; 15…Operation section; 16…Image reading section; 17…Automatic feeding 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…Storage chamber; 30…Outlet section; 31…Storage section side valve; 33…First storage section; 34…Communication path; 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…Pressurizing section; 48…Switching mechanism; 49…Pressure sensor; 50…Atmospheric opening path; 51…Pressurizing flow path; 52…Connection flow path; 53…Air chamber; 54…Spring; 55…Air flow path; 57…Pressurizing mechanism; 58…Micro-pressurizing section; 60…Inlet section; 61…Device side valve; 62…First storage chamber; 63…Liquid quantity sensor; 64…First gas-liquid separation membrane; 65…Top; 66…First liquid level; 68…Second storage chamber; 69…Second gas-liquid separation membrane; 70…Second liquid level; 72…Capillary section; 73a…First selection valve; 73b…Second selection valve; 73c…Third selection valve; 73d…Fourth selection valve; 73e…Fifth selection valve; 73f…Sixth selection valve; 73g…Seventh selection valve; 73h…Eighth selection valve; 73i…Ninth selection valve; 73j…Tenth selection valve; 73k…Eleventh selection valve; 111…Liquid ejection device; 112…Medium; 113…Medium storage section; 114…Stacker; 115…Operation section; 116…Image reading section; 117…Automatic feeding section; 119…Control section; 121…Nozzle surface; 122…Nozzle; 123…Liquid ejection head; 124…Liquid storage section; 125…Supply mechanism; 126…Drive mechanism; 128…Mounting section; 129…Inlet flow path; 130…Inlet valve; 133…First storage section; 134…Communication path; 135…Second storage section; 136…First valve; 137…Supply flow path; 138…Second valve; 139…Recovery flow path; 140…Third valve; 141…Liquid chamber; 142…Flexible member; 144…First connection section; 145…Second connection section; 147…Pressure variable mechanism; 148…Decompression flow path; 149…Pressure sensor; 150…Atmospheric opening path; 151…Pressurizing flow path; 153…Air chamber; 154…Spring; 155…Air flow path; 157…Pressurizing mechanism; 158…Micro-pressurizing section; 160…Decompression chamber; 161…Float valve; 162…First storage chamber; 163…Liquid quantity sensor; 164…First gas-liquid separation membrane; 165…Sealing member; 166…First liquid level; 168…Second storage chamber; 169…Second gas-liquid separation membrane; 170…Second liquid level; 172…Capillary section; 173a…First selection valve;173b…Second selection valve; 173c…Third selection valve; 173d…Fourth selection valve; 173e…Fifth selection valve; 173f…Sixth selection valve; 173g…Seventh selection valve; 173h…Eighth selection valve; 173i…Ninth selection valve.; Detailed implementation manner

[0026] First implementation manner

[0027] Hereinafter, a first implementation manner of a liquid ejection device and a control method of the liquid ejection device will be described with reference to the accompanying drawings. The liquid ejection device is, for example, an inkjet printer that ejects ink, which is an example of a liquid, onto a medium such as paper for printing.

[0028] In the drawings, it is assumed that the liquid ejection device 11 is placed on a horizontal plane, the Z-axis represents the direction of gravity, and the X-axis and Y-axis represent the directions along the horizontal plane. The X-axis, Y-axis, and Z-axis are orthogonal to each other.

[0029] As Figure 1 shown, the liquid ejection device 11 may also include a medium accommodating portion 13 that can accommodate the medium 12, a stacker 14 that receives the printed medium 12, and an operation portion 15 such as a touch panel for operating the liquid ejection device 11. The liquid ejection device 11 may also include an image reading portion 16 that reads an image of an original and an automatic feeding portion 17 that conveys the original to the image reading portion 16.

[0030] The liquid ejection device 11 includes a control portion 19 that controls various operations performed by the liquid ejection device 11. The control portion 19 is constituted by, for example, a processing circuit including a computer and a memory, and performs control according to a program stored in the memory.

[0031] As Figure 2 shown, the liquid ejection device 11 includes: a liquid ejection head 23 that ejects a liquid from nozzles 22 provided on a nozzle surface 21; a supply mechanism 25 that supplies the liquid accommodated in a liquid accommodation portion 24 to the liquid ejection head 23; and a drive mechanism 26 that drives the supply mechanism 25. The liquid ejection device 11 may also include a plurality of supply mechanisms 25. The plurality of supply mechanisms 25 may supply different types of liquids to the liquid ejection head 23, respectively. For example, the liquid ejection device 11 may eject inks of multiple colors supplied by the plurality of supply mechanisms 25 to perform color printing. One drive mechanism 26 may drive the plurality of supply mechanisms 25 in a unified manner. The liquid ejection device 11 may also include a plurality of drive mechanisms 26 that individually drive the plurality of supply mechanisms 25.

[0032] The liquid ejection head 23 can also be configured to be detachable from the main body of the liquid ejection device 11. The liquid ejection head 23 is arranged in an inclined posture with the nozzle surface 21 inclined with respect to the horizontal. The liquid ejection head 23 can also perform printing by ejecting liquid onto the medium 12 in the inclined posture. The liquid ejection head 23 of the present embodiment is a line head arranged in the entire width direction of the medium 12. The liquid ejection head 23 can also be configured as a serial head that performs printing while moving in the width direction of the medium 12.

[0033] The supply mechanism 25 can also include a mounting portion 28 for detachably mounting the liquid storage portion 24. The liquid storage portion 24 can also include a storage chamber 29 for storing liquid, a discharge portion 30 for discharging the liquid stored in the storage chamber 29, and a storage portion side valve 31 provided in the discharge portion 30. The storage chamber 29 of the present embodiment is a closed space not communicating with the atmosphere. The liquid storage portion 24 before being mounted on the mounting portion 28 can also store a larger amount of liquid than the amount of liquid that the supply mechanism 25 can hold.

[0034] The supply mechanism 25 includes a first storage portion 33 for storing the liquid supplied from the liquid storage portion 24, a communication path 34 with its upstream end connected to the first storage portion 33, and a second storage portion 35 connected to the downstream end of the communication path 34. That is, the second storage portion 35 communicates with the first storage portion 33 via the communication path 34. The supply mechanism 25 includes a first valve 36 capable of closing the communication path 34 and a supply flow path 37 for supplying liquid from the second storage portion 35 to the liquid ejection head 23. The supply mechanism 25 can also include a second valve 38 provided in the supply flow path 37 between the second storage portion 35 and the liquid ejection head 23, a recovery flow path 39 for recovering the liquid from the liquid ejection head 23 to the first storage portion 33, a third valve 40 capable of opening and closing the recovery flow path 39, and a liquid chamber 41 provided in the recovery flow path 39.

[0035] The liquid chamber 41 is provided in the recovery flow path 39 between the liquid ejection head 23 and the third valve 40. A part of the liquid chamber 41 is formed by a flexible member 42, and the volume changes as the flexible member 42 deforms.

[0036] The liquid ejection head 23 can also have a first connection portion 44 to which the recovery flow path 39 is connected and a second connection portion 45 to which the supply flow path 37 is connected. The upstream end of the recovery flow path 39 is connected to the first connection portion 44, and the downstream end is connected to the first storage portion 33. The upstream end of the supply flow path 37 is connected to the second storage portion 35, and the downstream end is connected to the second connection portion 45. In the inclined posture, the first connection portion 44 of the liquid ejection head 23 and the recovery flow path 39 can also be arranged at a position higher than the second connection portion 45 of the liquid ejection head 23 and the supply flow path 37.

[0037] The drive mechanism 26 includes a pressurizing section 47 that pressurizes the interior of the second storage section 35. The drive mechanism 26 may also include a switching mechanism 48 connected to the pressurizing section 47 and a pressure sensor 49 that detects pressure. The drive mechanism 26 may also include an atmospheric opening path 50 connected to the first storage section 33, a pressurizing flow path 51 connected to the second storage section 35, and a connection flow path 52 that connects the atmospheric opening path 50 and the pressurizing flow path 51 to the pressurizing section 47. The drive mechanism 26 may also include an air chamber 53 separated from the liquid chamber 41 by a flexible member 42, a spring 54 disposed within 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 within the recovery flow path 39 and the liquid ejection head 23.

[0038] The pressurizing section 47 is, for example, a tube pump that sends out air by rotating while crimping the tube edge. One end of an unillustrated tube included in the pressurizing section 47 is connected to the air flow path 55, and the other end is connected to the connection flow path 52. By driving the pressurizing section 47 in the forward rotation, the air introduced from the air flow path 55 is sent to the connection flow path 52. By driving the pressurizing section 47 in the reverse rotation, the air introduced from the connection flow path 52 is sent to the air flow path 55.

[0039] In the present embodiment, a pressurizing mechanism 57 is constituted by including the pressurizing section 47, the air chamber 53, and the air flow path 55 that communicates the pressurizing section 47 with the air chamber 53, and a micro-pressurizing section 58 is constituted by adding the liquid chamber 41 to the pressurizing mechanism 57. The micro-pressurizing section 58 has the liquid chamber 41 and a pressurizing mechanism 57 that can pressurize the flexible member 42 from the outside of the liquid chamber 41. The micro-pressurizing section 58 is provided in the recovery flow path 39 between the liquid ejection head 23 and the third valve 40 and pressurizes the liquid within the recovery flow path 39.

[0040] Next, the first storage section 33 will be described.

[0041] The first storage section 33 has an introduction section 60 that can introduce the liquid accommodated in the liquid accommodation section 24 installed on the installation section 28. The first storage section 33 may also have a device-side valve 61 provided in the introduction section 60, a first storage chamber 62 that stores the liquid, a liquid amount sensor 63 that detects the amount of the liquid stored in the first storage chamber 62, and a first gas-liquid separation membrane 64 that separates the first storage chamber 62 from the atmospheric opening path 50. The first gas-liquid separation membrane 64 is a membrane having the property of allowing gas to pass through but not allowing liquid to pass through.

[0042] The container-side valve 31 and the device-side valve 61 are opened when the liquid container 24 is mounted on the mounting portion 28, and remain open during the period when the liquid container 24 is mounted on the mounting portion 28. By configuring the device-side valve 61 to open before the container-side valve 31 when the liquid container 24 is mounted on the mounting portion 28, the possibility of liquid leaking from the liquid container 24 can be reduced.

[0043] The introduction portion 60 is provided above the first storage portion 33. The introduction portion 60 of the present embodiment is provided so as to penetrate the top portion 65 of the first storage chamber 62. The lower end of the introduction portion 60 is located at a position below the top portion 65 in the first storage chamber 62. The upper end of the introduction portion 60 is located at a position above the top portion 65 outside the first storage chamber 62. By mounting the liquid container 24 on the mounting portion 28, the introduction portion 60 is connected to the discharge portion 30 provided in the liquid container 24.

[0044] The lower end of the introduction portion 60 is located at a position below the nozzle surface 21. Accordingly, the first liquid level 66 of the liquid stored in the first storage portion 33 varies within a range lower than the nozzle surface 21. Specifically, the liquid in the liquid container 24 is supplied to the first storage portion 33 via the discharge portion 30 and the introduction portion 60 due to the head. An amount of air corresponding to the liquid supplied to the first storage portion 33 is introduced from the first storage portion 33 into the liquid container 24 via the introduction portion 60 and the discharge portion 30. The first liquid level 66 rises by an amount corresponding to the supplied liquid. When the first liquid level 66 reaches the lower end of the introduction portion 60, the inflow of air from the first storage portion 33 into the liquid container 24 is restricted. Since the accommodation chamber 29 is sealed, when the inflow of air is restricted, the pressure in the accommodation chamber 29 drops by an amount corresponding to the supplied liquid. When the negative pressure in the accommodation chamber 29 becomes greater than the head of the liquid in the accommodation chamber 29, the supply of liquid from the liquid container 24 to the first storage portion 33 is restricted.

[0045] The first liquid level 66 drops due to the supply of liquid from the first storage portion 33 to the second storage portion 35. When the first liquid level 66 drops and air flows into the accommodation chamber 29 via the introduction portion 60 and the discharge portion 30, the negative pressure in the accommodation chamber 29 becomes smaller. When the negative pressure in the accommodation chamber 29 becomes smaller than the head of the liquid in the accommodation chamber 29, liquid is supplied from the liquid container 24 to the first storage portion 33. Therefore, during the period when the liquid container 24 contains liquid, the first liquid level 66 is maintained at a position near the lower end of the introduction portion 60, i.e., the standard position. When the liquid contained in the liquid container 24 runs out, the first liquid level 66 is located below the standard position.

[0046] The liquid level sensor 63 can also detect that the first liquid level 66 is at the standard position, below the standard position, or at the full position above the standard position. When the first liquid level 66 is at the full position, the first storage unit 33 stores the maximum amount of liquid. The control unit 19 can also determine that the liquid containing unit 24 is empty when the liquid level sensor 63 detects that the first liquid level 66 is below the standard position, and instruct the user to replace the liquid containing unit 24.

[0047] In the present embodiment, the standard position in the first storage chamber 62 is above the position where the downstream end of the recovery flow path 39 is connected. Therefore, when the first liquid level 66 is at the standard position, the liquid in the first storage unit 33 can be supplied to the liquid ejection head 23 via the recovery flow path 39.

[0048] Next, the second storage unit 35 will be described.

[0049] The second storage unit 35 may also include a second storage chamber 68 for storing liquid and a second gas-liquid separation membrane 69 that separates the second storage chamber 68 from the pressurization flow path 51. Similar to the first gas-liquid separation membrane 64, the second gas-liquid separation membrane 69 is a membrane that has the property of allowing gas to pass through while not allowing liquid to pass through.

[0050] Liquid is supplied from the first storage unit 33 to the second storage unit 35 by the head difference. The first valve 36 may also be configured to have a check valve that allows liquid to flow from the first storage unit 33 to the second storage unit 35 and restricts liquid from flowing from the second storage unit 35 to the first storage unit 33. When the pressure in the first storage chamber 62 and the second storage chamber 68 is atmospheric pressure, the second liquid level 70 of the liquid in the second storage unit 35 is at the same height as the first liquid level 66. In other words, the second liquid level 70 is maintained at the standard position that is approximately the same height as the lower end of the introduction portion 60, and varies within a range lower than the nozzle surface 21. The liquid in the liquid ejection head 23 is maintained at a negative pressure due to the head difference with the liquid in the first storage unit 33 and the second storage unit 35. When the liquid is consumed in the liquid ejection head 23, the liquid stored in the second storage unit 35 is supplied to the liquid ejection head 23.

[0051] The first valve 36 closes the communication path 34 when the pressure in the second storage unit 35 is greater than the pressure in the first storage unit 33. Therefore, when the second storage unit 35 is pressurized by the pressurization unit 47, the first valve 36 blocks the communication path 34.

[0052] The opening and closing of the second valve 38 and the third valve 40 are controlled by the control unit 19. The second valve 38 is arranged to be able to open and close the supply flow path 37 when the pressurization unit 47 pressurizes. The third valve 40 is arranged to be able to open and close the recovery flow path 39.

[0053] Next, the switching mechanism 48 will be described.

[0054] The switching mechanism 48 includes a thin tube portion 72 provided in the connection flow path 52 and first to eleventh selection valves 73a to 73k capable of opening and closing the flow path. The thin tube portion 72 is a tube that is thin enough to greatly restrict the flow of liquid relative to the flow of air and is tortuous.

[0055] The first selection valve 73a communicates the air flow path 55 with the atmosphere by opening the valve. The second selection valve 73b communicates the air flow path 55 with the pressure sensor 49 by opening the valve. The third selection valve 73c opens the air flow path 55 by opening the valve and communicates the pressurizing portion 47 with the air chamber 53.

[0056] The fourth selection valve 73d communicates the connection flow path 52 between the pressurizing portion 47 and the eighth selection valve 73h with the atmosphere by opening the valve. The fifth selection valve 73e communicates the connection flow path 52 with the pressure sensor 49 by opening the valve. The sixth selection valve 73f and the seventh selection valve 73g communicate the connection flow path 52 with the atmosphere by opening the valve. The eighth selection valve 73h opens the connection flow path 52 by opening the valve. The ninth selection valve 73i communicates the thin tube portion 72 with the atmosphere by opening the valve. The tenth selection valve 73j opens the atmosphere opening path 50 by opening the valve and communicates the first storage portion 33 with the connection flow path 52. The eleventh selection valve 73k opens the pressurizing flow path 51 by opening the valve and communicates the second storage portion 35 with the connection flow path 52.

[0057] When changing the pressure in the air chamber 53, the switching mechanism 48 opens the second selection valve 73b to the fourth selection valve 73d and closes the other selection valves. When the pressurizing portion 47 is driven forward in this state, the air in the air chamber 53 is discharged via the air flow path 55 and the connection flow path 52, and the pressure in the air chamber 53 decreases. When the pressurizing portion 47 is driven in reverse in this state, air is sent into the air chamber 53 via the connection flow path 52 and the air flow path 55, and the pressure in the air chamber 53 increases. At this time, the pressure sensor 49 can also detect the pressure in the air flow path 55 and the air chamber 53. The control unit 19 can also control the drive of the pressurizing portion 47 based on the detection result of the pressure sensor 49.

[0058] When opening the first storage portion 33 to the atmosphere, the switching mechanism 48 opens the sixth selection valve 73f and the tenth selection valve 73j. The first storage chamber 62 communicates with the atmosphere via the atmosphere opening path 50 and the connection flow path 52.

[0059] When opening the second storage portion 35 to the atmosphere, the switching mechanism 48 opens the seventh selection valve 73g and the eleventh selection valve 73k. The second storage chamber 68 communicates with the atmosphere via the pressurizing flow path 51 and the connection flow path 52.

[0060] When the second storage unit 35 is pressurized, the switching mechanism 48 opens the first selection valve 73a, the fifth selection valve 73e, the eighth selection valve 73h, and the eleventh selection valve 73k, and closes the other selection valves. When the pressurizing unit 47 is driven to rotate forward in this state, air flows into the second storage chamber 68 through the air flow path 55, the connection flow path 52, and the pressurizing flow path 51, and the pressure in the second storage chamber 68 rises. At this time, the pressure sensor 49 can also detect the pressures in the connection flow path 52, the pressurizing flow path 51, and the second storage chamber 68. The control unit 19 can also control the drive of the pressurizing unit 47 based on the detection result of the pressure sensor 49.

[0061] Next, with reference to Figures 3 to 9 the flowchart shown, the control method of the liquid ejection device 11 will be described. Here, the step order of each control method can be arbitrarily replaced within the range not departing from the purpose of each control method.

[0062] Figure 3 The liquid filling routine shown can be executed at the timing when the liquid containing unit 24 is started to be installed in the installation unit 28. The liquid filling routine can also be executed at the timing when the liquid containing unit 24 is installed in the installation unit 28 after replacing the liquid ejection head 23. In the initial state, all the selection valves of the second valve 38, the third valve 40, and the switching mechanism 48 are closed.

[0063] In step S101, the control unit 19 opens the second storage unit 35 to the atmosphere. In step S102, the control unit 19 opens the first storage unit 33 to the atmosphere. In step S103, the control unit 19 determines whether the first liquid level 66 is at the standard position. When the first liquid level 66 is not at the standard position, step S103 is NO, and the control unit 19 stands by until the first liquid level 66 reaches the standard position. When the first liquid level 66 is at the standard position, step S103 is YES, and the control unit 19 transfers the process to step S104.

[0064] In step S104, the control unit 19 opens the second valve 38. In step S105, the control unit 19 opens the third valve 40. In step S106, the control unit 19 pressurizes the second storage unit 35.

[0065] In step S107, the control unit 19 determines whether the first liquid level 66 is at the full position. When the first liquid level 66 is not at the full position, step S107 is NO, and the control unit 19 stands by until the first liquid level 66 reaches the full position. When the first liquid level 66 is at the full position, step S107 is YES, and the control unit 19 transfers the process to step S108.

[0066] In step S108, the control unit 19 closes the third valve 40. In step S109, the control unit 19 determines whether the filling time has elapsed since the third valve 40 was closed. The filling time is the time required to fill the liquid from the supply flow path 37 to the nozzle 22. If the filling time has not elapsed, the answer in step S109 is no, and the control unit 19 stands by until the filling time has elapsed. When the filling time has elapsed, the answer in step S109 is yes, and the control unit 19 transfers the process to step S110. In step S110, the control unit 19 stops the drive of the pressurizing unit 47. In step S111, the control unit 19 opens the second storage unit 35 to the atmosphere and ends the liquid filling routine.

[0067] Here, step S104 and step S105 may also be performed simultaneously with step S106, respectively, or after step S106. In addition, step S110 may also be performed simultaneously with step S111, or after step S111.

[0068] Next, the operation during liquid filling will be described.

[0069] As Figure 2 shown, when the liquid storage unit 24 is installed on the installation unit 28 and the first storage unit 33 is open to the atmosphere, the liquid is supplied from the liquid storage unit 24 to the first storage unit 33. Since the second storage unit 35 is also open to the atmosphere at this time, the liquid supplied to the first storage unit 33 also flows into the second storage unit 35. The first liquid level 66 and the second liquid level 70 rise to the standard position.

[0070] When the control unit 19 detects that the first liquid level 66 is at the standard position through the liquid amount sensor 63, the control unit 19 opens the second valve 38 and the third valve 40, and drives the pressurizing unit 47. When the pressure in the second storage unit 35 is higher than the pressure in the first storage unit 33, the first valve 36 closes and the communication path 34 is closed. Therefore, the liquid in the second storage unit 35 flows into the first storage unit 33 via the supply flow path 37, the liquid ejection head 23, and the recovery flow path 39.

[0071] When the control unit 19 detects that the first liquid level 66 is at the full position through the liquid amount sensor 63, the control unit 19 closes the third valve 40. As a result, the liquid stops flowing into the first storage unit 33. The liquid in the second storage unit 35 is filled into the liquid ejection head 23 and discharged from the nozzle 22.

[0072] When filling the liquid into the liquid ejection head 23, the control unit 19 opens the second storage unit 35 to the atmosphere. As a result, the first valve 36 opens and the communication path 34 is opened. The liquid in the first storage unit 33 is supplied to the second storage unit 35 via the communication path 34. The control unit 19 may also close the second valve 38.

[0073] Figure 4 The liquid circulation routine shown can also be executed at the timing indicating the execution of liquid circulation. For example, the liquid circulation is indicated during the standby period after liquid filling and before printing or the like. The control unit 19 can also execute the liquid circulation routine regularly.

[0074] 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 inside of the second storage unit 35.

[0075] In step S205, the control unit 19 determines whether the first liquid level 66 is at the full position. When the first liquid level 66 is not at the full position, step S205 is NO, and the control unit 19 stands by until the first liquid level 66 reaches the full position. When the first liquid level 66 is at the full position, step S205 is YES, and the control unit 19 transfers 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.

[0076] Here, step S201 and step S202 can be performed simultaneously with step S203 or after step S203, and can also be performed simultaneously with step S204 or after step S204. In addition, step S206 can be performed simultaneously with step S207 or after step S207.

[0077] Next, the operation during liquid circulation will be described.

[0078] As Figure 2 shown, the control unit 19 opens the second valve 38 to open the supply flow path 37 through the second valve 38. The control unit 19 opens the third valve 40 to open the recovery flow path 39 through the third valve 40.

[0079] The liquid ejection device 11 pressurizes the inside of the second storage unit 35 through the pressurizing unit 47, so that the liquid flows from the second storage unit 35 through the liquid ejection head 23 to the first storage unit 33. At this time, the pressure in the second storage unit 35 is higher than the pressure in the first storage unit 33. Therefore, the first valve 36 is closed. That is, the liquid ejection device 11 pressurizes the inside of the second storage unit 35 to close the communication path 34 by using the first valve 36.

[0080] Figure 5 The printing routine shown can also be executed at the timing indicating printing.

[0081] 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.

[0082] In step S304, the control unit 19 determines whether the liquid ejection flow rate generated by ejecting the liquid from the nozzle 22 during printing is equal to or greater than the threshold value. The control unit 19 may also calculate the ejection flow rate based on the print data. When the ejection flow rate is equal to or greater than the threshold value, step S304 is YES, and the control unit 19 transfers the process to step S305. In step S305, the control unit 19 opens the third valve 40.

[0083] In step S304, when the ejection flow rate is less than the threshold value, step S304 is NO, and the control unit 19 transfers 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 printing routine.

[0084] Here, step S301 and step S302 may be performed simultaneously with step S303 or after step S303, may be performed simultaneously with step S305 or after step S305, and may also be performed simultaneously with step S306 or after step S306.

[0085] Next, the operation during the execution of the printing routine will be described.

[0086] As Figure 2 shown, when the ejection flow rate when the liquid ejection head 23 ejects the liquid onto the medium 12 is less than the 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 where 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, the liquid is supplied from the second storage unit 35 to the liquid ejection head 23 via the supply flow path 37.

[0087] When the ejection flow rate when the liquid ejection head 23 ejects the 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 in a state where the supply flow path 37 is opened by the second valve 38 and the recovery flow path 39 is opened by the third valve 40. Therefore, the liquid is supplied from the second storage unit 35 to the liquid ejection head 23 via the supply flow path 37, and the liquid is also supplied from the first storage unit 33 to the liquid ejection head 23 via the recovery flow path 39.

[0088] Figure 6 The pressurized discharge routine shown is executed when pressurized discharge is instructed, when an ejection failure occurs in which the liquid cannot be normally ejected from the nozzle 22, or the like.

[0089] In step S401, the control unit 19 opens the second valve 38. In step S402, the control unit 19 closes the third valve 40. In step S403, the control unit 19 pressurizes the interior of the second storage unit 35. In step S404, the control unit 19 determines whether the pressurization discharge time has elapsed since the interior of the second storage unit 35 was pressurized. The pressurization discharge time is the time required for the pressure of the second storage unit 35 to be transmitted through the supply flow path 37 to the nozzle 22 to discharge the liquid from the nozzle 22 and restore the state of the nozzle 22.

[0090] Before the pressurization discharge time has elapsed, step S404 is NO, and the control unit 19 stands by until the pressurization discharge time has elapsed. When the pressurization discharge time has elapsed, step S404 is YES, and the control unit 19 transfers the process to step S405. In step S405, the control unit 19 closes the second valve 38. In step S406, the control unit 19 opens the second storage unit 35 to the atmosphere and ends the pressurization discharge routine.

[0091] Here, step S401 and step S402 may be performed simultaneously with step S403, respectively, or after step S403. In addition, step S405 may be performed simultaneously with step S406, or after step S406.

[0092] Next, the operation during pressurization discharge will be described.

[0093] As Figure 2 shown, the liquid ejection device 11 pressurizes the interior of the second storage unit 35 through the pressurizing unit 47 and discharges the liquid from the nozzle 22. At this time, since the pressure of the second storage unit 35 is higher than the pressure of the first storage unit 33, the first valve 36 is closed. That is, the liquid ejection device 11 closes the communication path 34 by using the first valve 36 by pressurizing the second storage unit 35.

[0094] When the pressurization discharge time has elapsed since the interior of the second storage unit 35 was pressurized, the control unit 19 closes the second valve 38. Thereby, the discharge of the liquid from the nozzle 22 is stopped. When the second storage unit 35 is opened to the atmosphere, the first valve 36 is opened, and the liquid is supplied from the first storage unit 33 to the second storage unit 35.

[0095] Figure 7 The pressure accumulation discharge routine shown may also be executed in the case of instructing the execution of pressure accumulation discharge, the case where the ejection failure is not improved even if the pressure discharge is executed, etc.

[0096] In step S501, the control unit 19 closes the second valve 38. In step S502, the control unit 19 closes the third valve 40. In step S503, the control unit 19 determines whether to indicate the execution of the first pressure accumulation discharge during the pressure accumulation discharge or to indicate the execution of the second pressure accumulation discharge in which the accumulated pressure is less than the first pressure accumulation discharge. In the case of executing the first pressure accumulation discharge, if step S503 is affirmative, the control unit 19 transfers the process to step S504. In step S504, the control unit 19 sets the pressure accumulation time to the first time.

[0097] In step S503, in the case of executing the second pressure accumulation discharge, if step S503 is negative, the control unit 19 transfers the process to step S505. In step S505, the control unit 19 sets the pressure accumulation time to the second time shorter than the first time.

[0098] In step S506, the control unit 19 pressurizes the inside of the second storage unit 35. In step S507, the control unit 19 determines whether the pressure accumulation time has elapsed since the start of pressurizing the inside of the second storage unit 35. If the pressure accumulation time has not elapsed, if step S507 is negative, the control unit 19 stands by until the pressure accumulation time elapses. When the pressure accumulation time elapses, if step S507 is affirmative, the control unit 19 transfers the process to step S508.

[0099] In step S508, the control unit 19 opens the second valve 38. In step S509, the control unit 19 determines whether the pressure accumulation discharge time has elapsed since the opening of the second valve 38. The pressure accumulation 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 to discharge the liquid from the nozzle 22.

[0100] Before the pressure accumulation discharge time elapses, if step S509 is negative, the control unit 19 stands by until the pressure accumulation discharge time elapses. When the pressure accumulation discharge time elapses, if step S509 is affirmative, the control unit 19 transfers the process to step S510. In step S510, the control unit 19 closes the second valve 38. In step S511, the control unit 19 opens the second storage unit 35 to the atmosphere and ends the pressure accumulation discharge routine.

[0101] Here, step S501 and step S502 may also be performed simultaneously with the start of pressurization in step S506, or may be performed after the start of pressurization in step S506. In addition, step S510 may be performed simultaneously with step S511, or may be performed after step S511. In addition, step S510 may not be performed.

[0102] Next, the operation during the pressure accumulation discharge will be described.

[0103] As Figure 2As shown, the control unit 19 closes the second valve 38 to close the supply flow path 37 through the second valve 38. The liquid ejecting device 11 pressurizes the inside of the second storage unit 35 through the pressurizing unit 47. At this time, since the pressure in the second storage unit 35 is higher than the pressure in the first storage unit 33, the first valve 36 closes. That is, the liquid ejecting device 11 pressurizes the second storage unit 35 to close the communication path 34 by using the first valve 36.

[0104] After the liquid ejecting device 11 pressurizes the inside of the second storage unit 35 through the pressurizing unit 47, the liquid ejecting device 11 opens the supply flow path 37 through the second valve 38 to discharge the liquid from the nozzle 22. The magnitude of the pressure accumulated in the second storage unit 35 is proportional to the time for pressurizing the inside of the second storage unit 35 in a state where the communication path 34 and the supply flow path 37 are blocked. In the first pressure accumulation discharge, the time for pressurizing the inside of the second storage unit 35 through the pressurizing unit 47 is the first time. In the second pressure accumulation discharge, the time for pressurizing the inside of the second storage unit 35 through the pressurizing unit 47 is the second time shorter than the first time. The pressure accumulated through the first pressure accumulation discharge is greater than the pressure accumulated through the second pressure accumulation discharge. That is, in the first pressure accumulation discharge, the supply flow path 37 is opened through the second valve 38 when the inside of the second storage unit 35 is pressurized at the first pressure. In the second pressure accumulation discharge, the supply flow path 37 is opened through the second valve 38 when the inside of the second storage unit 35 is pressurized at the second pressure lower than the first pressure.

[0105] When the pressure accumulation discharge time has elapsed since the start of pressurizing the inside of the second storage unit 35, the control unit 19 closes the second valve 38. Thereby, the discharge of the liquid from the nozzle 22 is stopped. When the second storage unit 35 is opened to the atmosphere, the first valve 36 opens, and the liquid is supplied from the first storage unit 33 to the second storage unit 35.

[0106] Figure 8 The micro pressurization discharge routine shown can also be executed when micro pressurization discharge is instructed.

[0107] 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 the depressurization time has elapsed since the start of depressurizing the air chamber 53. The depressurization time is the time required to deform the flexible member 42 to maximize the volume of the liquid chamber 41.

[0108] Before the decompression time has elapsed, the answer in step S604 is no, and the control unit 19 stands by until the decompression time has elapsed. When the decompression time has elapsed, the answer in step S604 is yes, and the control unit 19 transfers the process 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.

[0109] In step S608, the control unit 19 determines whether the micro-pressurization time has elapsed since the air chamber 53 was pressurized. The micro-pressurization time is the time required for the pressure that pressurizes the air chamber 53 to be transmitted to the nozzle 22 via the liquid chamber 41 and the recovery flow path 39.

[0110] Before the micro-pressurization time has elapsed, the answer in step S608 is no, and the control unit 19 stands by until the micro-pressurization time has elapsed. When the micro-pressurization time has elapsed, the answer in step S608 is yes, and the control unit 19 transfers the process to step S609. In step S609, the control unit 19 opens the air chamber 53 to the atmosphere and ends the micro-pressurization discharge routine.

[0111] Here, step S601 and step S602 may also be performed simultaneously with step S603, or after step S603. In addition, step S605 and step S606 may be performed respectively while step S603 is in progress, may be performed simultaneously with the end of step S603, or may be performed after the end of step S603. In addition, step S605 and step S606 may also be performed simultaneously with step S607, or after step S607.

[0112] Next, the operation during micro-pressurization discharge will be described.

[0113] As Figure 2 shown, the control unit 19 opens the supply flow path 37 and the recovery flow path 39 by opening the second valve 38 and the third valve 40. The control unit 19 decompresses the air chamber 53 to deform the flexible member 42 to increase the volume of the liquid chamber 41. Liquid flows from the first storage unit 33 into the liquid chamber 41 via the recovery flow path 39, and liquid flows from the second storage unit 35 into the liquid chamber 41 via the supply flow path 37 and the recovery flow path 39.

[0114] When the volume of the liquid chamber 41 reaches its maximum, the control unit 19 closes the second valve 38 to shut off the supply flow path 37 via the second valve 38. The control unit 19 closes the third valve 40 to shut off the recovery flow path 39 via the third valve 40. In this state, the liquid ejecting device 11 supplies pressurized air to the air chamber 53 through the pressurizing unit 47 to pressurize the flexible member 42. That is, the liquid ejecting device 11 pressurizes the flexible member 42 through the pressurizing mechanism 57 to eject the liquid from the nozzle 22. The pressurizing mechanism 57 pressurizes the liquid chamber 41 with a pressure that breaks the liquid meniscus formed at the nozzle 22. The amount of liquid ejected from the liquid ejection head 23 by micro-pressurized ejection is less than the amount of liquid ejected from the liquid ejection head 23 by pressurized ejection.

[0115] Figure 9 The head replacement routine shown can also be executed when replacing the liquid ejection head 23.

[0116] In step S701, the control unit 19 determines whether the liquid storage unit 24 has been removed from the mounting unit 28. When the liquid storage unit 24 is being mounted on the mounting unit 28, step S701 is NO, and the control unit 19 stands by until the liquid storage unit 24 is removed. When the liquid storage unit 24 is removed, step S701 is YES, and the control unit 19 transfers the process to step S702.

[0117] 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 inside of the second storage unit 35. In step S705, the control unit 19 determines whether the first discharge time has elapsed since the inside of 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.

[0118] Before the first discharge time elapses, step S705 is NO, and the control unit 19 stands by until the first discharge time elapses. When the first discharge time elapses, step S705 is YES, and the control unit 19 transfers the process to step S706. In step S706, the control unit 19 opens the third valve 40.

[0119] 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 flow path 39 to the first storage unit 33.

[0120] Before the second discharge time has elapsed, step S707 is NO, and the control unit 19 stands by until the second discharge time has elapsed. When the second discharge time has elapsed, step S707 is YES, and the control unit 19 transfers 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.

[0121] 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 yet, step S711 is NO, and the control unit 19 stands by until the liquid ejection head 23 is replaced. When the liquid ejection head 23 has been replaced, step S711 is YES, and the control unit 19 ends the head replacement routine.

[0122] Here, step S702 and step S703 may also be performed simultaneously with the start of pressurization in step S704, or may be performed after the start of pressurization in step S704. In addition, step S708 and step S709 may also be performed simultaneously with step S710, or may be performed after step S710.

[0123] Next, the head replacement routine will be described.

[0124] As Figure 2 shown, when replacing the liquid ejection head 23, the operator executes the head replacement routine and removes the liquid storage unit 24 from the mounting unit 28. Subsequently, the control unit 19 opens the second valve 38 to open the supply flow path 37 through the second valve 38. The control unit 19 closes the third valve 40 to close the recovery flow path 39 through the third valve 40. In this state, the control unit 19 pressurizes the inside of the second storage unit 35.

[0125] Specifically, the liquid ejection device 11 pressurizes the inside of the second storage unit 35 through the pressurizing unit 47 and discharges the liquid from the second storage unit 35 to the liquid ejection head 23 from the nozzle 22. At this time, since the pressure in the second storage unit 35 is higher than the pressure in the first storage unit 33, the first valve 36 closes. That is, the liquid ejection device 11 closes the communication path 34 by using the first valve 36 by pressurizing the second storage unit 35.

[0126] When discharging the liquid in the second storage unit 35, the supply flow path 37, and the liquid ejection head 23, the control unit 19 opens the third valve 40 to open the recovery flow path 39 through the third valve 40. That is, the liquid ejection device 11 pressurizes the inside of the second storage unit 35 through the pressurizing unit 47 and recovers the liquid in the recovery flow path 39 into the first storage unit 33. The operator replaces the liquid ejection head 23 in a state where the liquid has been removed from the supply flow path 37, the liquid ejection head 23, and the recovery flow path 39.

[0127] The effects of this embodiment will be described.

[0128] (1) A communication path 34 communicating with the first storage unit 33 and a supply flow path 37 communicating with the liquid ejection head 23 are connected to the second storage unit 35. The communication path 34 can be closed by the first valve 36 when the pressure in the second storage unit 35 is increased by the pressurizing unit 47. Therefore, the liquid in the pressurized second storage unit 35 is supplied to the liquid ejection head 23 via the supply flow path 37. Accordingly, the liquid ejection device 11 can eject the liquid from the nozzle 22 by pressurizing the liquid in the liquid ejection head 23, and can reduce the possibility of the liquid ejection head 23 sucking the liquid from the nozzle 22.

[0129] (2) When the pressurizing unit 47 pressurizes the inside of the second storage unit 35 in a state where the first valve 36 closes the communication path 34 and the second valve 38 closes the supply flow path 37, the pressure is accumulated in the second storage unit 35. Therefore, by opening the second valve 38 in a state where the pressure in the second storage unit 35 is increased, a high pressure can be transmitted to the liquid ejection head 23, and for example, a thickened liquid or the like can be easily ejected.

[0130] (3) When the pressurizing unit 47 pressurizes the inside of the second storage unit 35 in a state where the third valve 40 closes the recovery flow path 39, the liquid is ejected from the liquid ejection head 23. When the pressurizing unit 47 pressurizes the inside of the second storage unit 35 in a state where the third valve 40 opens the recovery flow path 39, the liquid in the liquid ejection head 23 is recovered into the first storage unit 33 through the recovery flow path 39. Therefore, for example, maintenance can be selected according to the state of the bubbles in the supply flow path 37 and the state of the nozzle 22 or the like.

[0131] (4) When the pressurizing mechanism 57 pressurizes the liquid chamber 41 in a state where the third valve 40 closes the recovery flow path 39, the liquid is ejected from the liquid ejection head 23. The amount of the liquid ejected at this time is determined by the size of the liquid chamber 41. Therefore, compared with the case where the inside of the second storage unit 35 is pressurized by the pressurizing unit 47, a micro-pressure that can accurately break the meniscus formed in the nozzle 22 can be applied to the liquid ejection head 23.

[0132] (5) The pressurizing mechanism 57 includes a pressurizing unit 47 that pressurizes the inside of the second storage unit 35. The pressurizing unit 47 pressurizes the air chamber 53 via the air flow path 55, thereby pressing the flexible member 42 and pressurizing the liquid chamber 41. Therefore, the liquid in the second storage unit 35 and the liquid in the liquid chamber 41 can be pressurized by the pressurizing unit 47.

[0133] (6) The first connection part 44 connected to the recovery flow path 39 is arranged at a position higher than the second connection part 45 connected to the supply flow path 37. Since the bubbles in the liquid ejection head 23 tend to gather at a higher position due to buoyancy, they are more likely to gather at the first connection part 44 than at the second connection part 45. Therefore, by recovering the liquid in the liquid ejection head 23 to the first storage part 33 via the recovery flow path 39, the bubbles can be easily discharged from the liquid ejection head 23.

[0134] (7) For example, when driving the first valve 36 to close the communication path 34, a driving 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 the liquid supplied from the first storage part 33 to the second storage part 35 due to the head difference, and restricts the flow of the liquid from the second storage part 35 to the first storage part 33 when the second storage part 35 is pressurized. Therefore, the first valve 36 does not require driving, and the driving source can be reduced.

[0135] (8) The nozzle surface 21 of the liquid ejection head 23 is inclined with respect to the horizontal. Therefore, the degree of freedom in arranging the liquid ejection head 23 can be improved.

[0136] (9) Regarding the pressure discharge, the communication path 34 is closed by the first valve 36, and the second storage part 35 is pressurized by the pressurizing part 47. The liquid in the pressurized second storage part 35 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 the possibility of the liquid ejection head 23 sucking the liquid from the nozzle 22 can be reduced.

[0137] (10) Regarding the pressure accumulation discharge, the second storage part 35 is pressurized by the pressurizing part 47 in a state where the first valve 36 closes the communication path 34 and the second valve 38 closes the supply flow path 37, so that the pressure is accumulated in the second storage part 35. In the pressure accumulation discharge, since the second valve 38 is opened after the second storage part 35 is pressurized, the accumulated high pressure can be transmitted to the liquid ejection head 23, and for example, thickened liquid or the like can be easily discharged.

[0138] (11) In the first pressure accumulation discharge, when the second storage part 35 is pressurized at the first pressure, the supply flow path 37 is opened by the second valve 38 to discharge the liquid from the nozzle 22. In the second pressure accumulation discharge, when the second storage part 35 is pressurized at the second pressure lower than the first pressure, the supply flow path 37 is opened by the second valve 38 to discharge the liquid from the nozzle 22. Therefore, for example, by combining the first pressure accumulation discharge and the second pressure accumulation discharge according to the structure of the supply flow path 37, the supply flow path 37 can be efficiently filled with liquid.

[0139] (12)Regarding the driving of the pressurizing unit 47 in a state where the communication path 34 and the supply flow path 37 are closed, the longer the driving time, the higher the accumulated pressure. In this regard, in the first pressure accumulation discharge, after pressurizing the inside of the second storage unit 35 for the first time, the supply flow path 37 is opened through the second valve 38 to discharge the liquid from the nozzle 22. In the second pressure accumulation discharge, after pressurizing the inside of the second storage unit 35 for the second time shorter than the first time, the supply flow path 37 is opened through the second valve 38 to discharge the liquid from the nozzle 22. Therefore, for example, by combining the first pressure accumulation discharge and the second pressure accumulation discharge according to the structure of the supply flow path 37, the supply flow path 37 can be efficiently filled with liquid.

[0140] (13)When liquid circulation is performed, the liquid is recovered from the second storage unit 35 to the first storage unit 33 via the supply flow path 37, the liquid ejection head 23, and the recovery flow path 39. The bubbles in the supply flow path 37 and the liquid ejection head 23 move together with the liquid. Therefore, the bubbles can be recovered without discharging the liquid from the liquid ejection head 23.

[0141] (14)Regarding the micro-pressurization discharge, in a state where the second valve 38 closes the supply flow path 37 and the third valve 40 closes the recovery flow path 39, the flexible member 42 is pressurized by the pressurizing mechanism 57, thereby pressurizing the liquid in the liquid chamber 41 and discharging the liquid from the liquid ejection head 23. The amount of the liquid discharged at this time is determined by the size of the liquid chamber 41. Therefore, compared with the case of pressurizing the inside of the second storage unit 35 by the pressurizing unit 47, a micro-pressurization that can precisely apply a degree to break the liquid meniscus formed in the nozzle 22 can be applied to the liquid ejection head 23.

[0142] (15)Regarding the micro-pressurization discharge, the pressurizing unit 47 pressurizes the air chamber 53 via the air flow path 55 and pressurizes the flexible member 42. Therefore, the liquid in the second storage unit 35 and the liquid in the liquid chamber 41 can be pressurized by the pressurizing unit 47.

[0143] (16)Regarding the head replacement routine, by pressurizing the inside of the second storage unit 35 in a state where the communication path 34 and the recovery flow path 39 are closed and the supply flow path 37 is opened, the liquid in the second storage unit 35, the supply flow path 37, and the liquid ejection head 23 is discharged from the nozzle 22. Then, by pressurizing the inside of the second storage unit 35 in a state where the communication path 34 is closed and the recovery flow path 39 and the supply flow path 37 are opened, the liquid in the recovery flow path 39 is recovered to the first storage unit 33. Therefore, since the liquid ejection head 23 is replaced in a state where the liquid has been discharged from the supply flow path 37, the liquid ejection head 23, and the recovery flow path 39, dripping of the liquid from the supply flow path 37, the liquid ejection head 23, and the recovery flow path 39 can be suppressed.

[0144] When the ejection flow rate during the ejection of the liquid onto the medium 12 is equal to or greater than the threshold value, the supply flow path 37 and the recovery flow path 39 are opened. Since the liquid is supplied to the liquid ejection head 23 not only from the supply flow path 37 but also from the recovery flow path 39, the required amount of liquid can be easily supplied.

[0145] The present embodiment can be implemented with the following modifications. The present embodiment and the following modification examples can be implemented in combination with each other within a technically non - conflicting range.

[0146] The liquid ejection device 11 may also include a wiping member (not shown) for wiping the nozzle surface 21. The liquid ejection device 11 may wipe the nozzle surface 21 with the wiping member after discharging the liquid from the nozzle 22. The liquid ejection device 11 may wipe the nozzle surface 21 before the operator removes the liquid ejection head 23.

[0147] The control unit 19 may also control the opening and closing of the first valve 36. The control unit 19 may block the communication path 34 through the first valve 36 before pressurizing the second storage unit 35.

[0148] The second pressure - accumulation discharge may also be performed by pressurizing the inside of the second storage unit 35 for a first time in a state where the first valve 36 and the second valve 38 are closed to make the pressure inside the second storage unit 35 become a first pressure, then opening the first valve 36 to reduce the pressure inside the second storage unit 35 to a second pressure, and then opening the second valve 38.

[0149] For the micro - pressurization discharge, the flexible member 42 may be pressed by the spring 54 to pressurize the liquid inside the liquid chamber 41. In this case, after the control unit 19 decompresses the air chamber 53 to increase the volume of the liquid chamber 41, the air chamber 53 is opened to the atmosphere. When the air chamber 53 reaches atmospheric pressure, the spring 54 presses the liquid inside the liquid chamber 41, causing the liquid to be discharged from the liquid ejection head 23. In the case of the structure where the flexible member 42 is pressed by the spring 54, the spring 54 is included in the pressurization mechanism 57.

[0150] The liquid ejection device 11 may also perform printing in a state where the recovery flow path 39 is opened by the third valve 40 regardless of the ejection flow rate.

[0151] The liquid ejection head 23 may also have a plurality of pressure chambers that communicate individually with a plurality of nozzles 22, a common liquid chamber that the plurality of pressure chambers communicate with, and a filter chamber that houses a filter. The first connection portion 44 and the second connection portion 45 are connected to at least one of the pressure chamber, the common liquid chamber, and the filter chamber. For example, in the case where the first connection portion 44 and the second connection portion 45 are connected to the filter chamber, the liquid ejection device 11 can recover the bubbles captured by the filter together with the liquid into the first storage portion 33 by performing liquid circulation. The liquid ejection device 11 may also perform liquid circulation when bubbles are generated inside the liquid ejection head 23.

[0152] When the liquid ejection device 11 is on standby and when the power is turned off, the second valve 38 and the third valve 40 may also 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, for example, even when the liquid ejection device 11 is subjected to vibration or impact, etc., the possibility of liquid leakage from the liquid ejection head 23 can be reduced.

[0153] The amount of liquid that the second storage portion 35 can store may also be less than the amount of liquid required for pressurized discharge. In this case, the control unit 19 may alternately execute: pressurizing the inside of the second storage portion 35 to supply liquid from the second storage portion 35 to the liquid ejection head 23; and opening the second storage portion 35 to the atmosphere to supply liquid from the first storage portion 33 to the second storage portion 35.

[0154] The liquid amount sensor 63 may also detect the end position where the first liquid level 66 is below the standard position. The control unit 19 may also notify that the first storage portion 33 is empty when the first liquid level 66 is detected at the end position by the liquid amount sensor 63. Regarding the end position, if the total amount of liquid stored in the first storage portion 33 and the second storage portion 35 when the first liquid level 66 and the second liquid level 70 are at the end position is greater than the amount of liquid required for printing one medium 12, then printing of one medium 12 can be completed.

[0155] The amount of liquid that the liquid storage portion 24 stores may also be less than the amount of liquid that the supply mechanism 25 can hold. In this case, the liquid storage portion 24 may also be replaced midway during liquid filling for filling the supply mechanism 25 with liquid.

[0156] The pressure accumulation discharge can also be performed by opening the supply flow path 37 through the second valve 38 when the pressure sensor 49 detects that the pressure has reached a specified pressure after pressurizing the second storage unit 35 in a state where the communication path 34 is closed by the first valve 36 and the supply flow path 37 is closed by the second valve 38. At this time, the control unit 19 can also perform: the first pressure accumulation discharge for opening the supply flow path 37 when the pressure sensor 49 detects that the pressure has reached the first pressure; and the second pressure accumulation discharge for opening the supply flow path 37 when it detects that the pressure has reached the second pressure which is smaller than the first pressure. The first pressure and the second pressure are greater than the pressurizing force for pressurizing the second storage unit 35 during the pressure accumulation discharge.

[0157] The control unit 19 can also depressurize the first storage unit 33 when causing the liquid to flow into the first storage unit 33 from the recovery flow path 39. For example, the atmosphere opening path 50 can also be connected to the air flow path 55. It is also possible to pressurize the second storage unit 35 by driving the pressurizing unit 47 to rotate forward, and depressurize the first storage unit 33 via the air flow path 55 and the atmosphere opening path 50.

[0158] The control unit 19 can also remove the bubbles from the liquid by depressurizing the first storage unit 33 and expanding the bubbles contained in the liquid stored in the first storage unit 33.

[0159] The liquid filling, the pressure accumulation discharge, the micro-pressure discharge, and the liquid circulation can be performed multiple times or can be combined. In the case where the amount of liquid that can be stored in the first storage unit 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, it is also possible to fill the supply flow path 37, the recovery flow path 39, and the liquid ejection head 23 with liquid by performing the liquid filling multiple times. For example, it is also possible to perform the micro-pressure discharge after the liquid filling. By combining the liquid filling and the micro-pressure discharge, the occurrence of ejection failures can be reduced compared to the case where only the liquid filling is performed.

[0160] The first storage unit 33 and the second storage unit 35 can also be integrally formed.

[0161] The flexible member 42 can also be formed of a rubber film, an elastomer film, a film, etc.

[0162] The liquid chamber 41 can also be provided in the supply flow path 37. The pressurizing mechanism 57 can also pressurize the liquid chamber provided in the supply flow path 37.

[0163] The pressurizing unit 47 can also use a diaphragm pump, a piston pump, a gear pump, etc.

[0164] The introduction unit 60 and the discharge unit 30 can also have a plurality of flow paths. For example, it is also possible that one flow path allows the liquid to flow from the liquid storage unit 24 into the first storage unit 33, and the other flow path allows the air to flow from the first storage unit 33 into the liquid storage unit 24.

[0165] The liquid ejection head 23 can also eject liquid in a horizontal posture with the nozzle surface 21 being horizontal to perform printing on the medium 12. The liquid ejection head 23 can also be configured to be able to change its posture between a horizontal posture and an inclined posture.

[0166] The liquid ejection device 11 can also include an atmosphere opening path that opens the second storage unit 35 to the atmosphere separately from the pressurizing flow path 51.

[0167] In Figure 9 In the head replacement routine shown, the control unit 19 can also execute steps S702 to S705 again after executing step S710. Thereby, the liquid recovered in the first storage unit 33 can be discharged from the liquid ejection head 23.

[0168] Second Embodiment

[0169] Hereinafter, a second embodiment of a liquid ejection device and a control method of the liquid ejection device will be described with reference to the drawings. The liquid ejection device is, for example, an inkjet printer that ejects ink, which is an example of a liquid, onto a medium such as paper for printing.

[0170] In the drawings, it is assumed that the liquid ejection device 111 is placed on a horizontal plane, the Z-axis represents the direction of gravity, and the X-axis and Y-axis represent directions along the horizontal plane. The X-axis, Y-axis, and Z-axis are orthogonal to each other.

[0171] As Figure 10 shown, the liquid ejection device 111 can also include a medium accommodating unit 113 that can accommodate the medium 112, a stacker 114 that receives the printed medium 112, and an operation unit 115 such as a touch panel for operating the liquid ejection device 111. The liquid ejection device 111 can also include an image reading unit 116 that reads an image of an original document and an automatic feeding unit 117 that conveys the original document to the image reading unit 116.

[0172] The liquid ejection device 111 includes a control unit 119 that controls various operations performed by the liquid ejection device 111. The control unit 119 is constituted by, for example, a processing circuit including a computer and a memory, and performs control according to a program stored in the memory.

[0173] As Figure 11As shown, the liquid ejection device 111 includes: a liquid ejection head 123 that ejects liquid from a nozzle 122 provided on a nozzle surface 121; a supply mechanism 125 that supplies the liquid accommodated in a liquid accommodation portion 124 to the liquid ejection head 123; and a drive mechanism 126 that drives the supply mechanism 125. The liquid ejection device 111 may also include a plurality of supply mechanisms 125. The plurality of supply mechanisms 125 may each supply different types of liquid to the liquid ejection head 123. For example, the liquid ejection device 111 may eject inks of multiple colors supplied by the plurality of supply mechanisms 125 to perform color printing. One drive mechanism 126 may uniformly drive the plurality of supply mechanisms 125. The liquid ejection device 111 may also include a plurality of drive mechanisms 126 that individually drive the plurality of supply mechanisms 125.

[0174] The liquid ejection head 123 may be configured to be detachable from the main body of the liquid ejection device 111. The liquid ejection head 123 is arranged in an inclined posture in which the nozzle surface 121 is inclined with respect to the horizontal. The liquid ejection head 123 may also perform printing by ejecting liquid in the inclined posture onto a medium 112. The liquid ejection head 123 of the present embodiment is a line head provided in the entire width direction of the medium 112. The liquid ejection head 123 may also be configured as a serial head that performs printing while moving in the width direction of the medium 112.

[0175] The supply mechanism 125 may also include: a mounting portion 128 to which the liquid accommodation portion 124 is detachably mounted, an introduction flow path 129 that can introduce liquid from the liquid accommodation portion 124 mounted on the mounting portion 128, and an introduction valve 130 that can open and close the introduction flow path 129. The liquid accommodation portion 124 before being mounted on the mounting portion 128 may accommodate a larger amount of liquid than the supply mechanism 125 can hold. The liquid accommodation portion 124 is connected to the upstream end of the introduction flow path 129 as it is mounted on the mounting portion 128. The introduction valve 130 is configured to have a check valve that allows liquid to flow from the liquid accommodation portion 124 to a first storage portion 133 and restricts liquid from flowing from the first storage portion 133 to the liquid accommodation portion 124.

[0176] The supply mechanism 125 includes: a first storage unit 133 that stores the liquid supplied from the liquid storage unit 124 that accommodates the liquid; a communication path 134 whose upstream end is connected to the first storage unit 133; and a second storage unit 135 to which the downstream end of the communication path 134 is connected. The downstream end of the introduction flow path 129 is connected to the first storage unit 133 of the present embodiment, and the first storage unit 133 communicates with the liquid storage unit 124 via the introduction flow path 129. The second storage unit 135 communicates with the first storage unit 133 via the communication path 134. The supply mechanism 125 includes: a first valve 136 that can open and close the communication path 134 and a supply flow path 137 that supplies the liquid from the second storage unit 135 to the liquid ejection head 123. The supply mechanism 125 may also include: a second valve 138 provided in the supply flow path 137 between the second storage unit 135 and the liquid ejection head 123, a recovery flow path 139 that recovers the liquid from the liquid ejection head 123 to the first storage unit 133, a third valve 140 that can open and close the recovery flow path 139, and a liquid chamber 141 provided in the recovery flow path 139.

[0177] The liquid chamber 141 is provided in the recovery flow path 139 between the liquid ejection head 123 and the third valve 140. A part of the liquid chamber 141 is constituted by a flexible member 142, and the volume changes as the flexible member 142 deforms.

[0178] The liquid ejection head 123 may also have a first connection portion 144 to which the recovery flow path 139 is connected and a second connection portion 145 to which the supply flow path 137 is connected. The upstream end of the recovery flow path 139 is connected to the first connection portion 144, and the downstream end is connected to the first storage unit 133. The upstream end of the supply flow path 137 is connected to the second storage unit 135, and the downstream end is connected to the second connection portion 145. In the inclined posture, the first connection portion 144 of the liquid ejection head 123 and the recovery flow path 139 may be arranged at a position higher than the second connection portion 145 of the liquid ejection head 123 and the supply flow path 137.

[0179] The drive mechanism 126 includes a pressure variable mechanism 147 that decompresses the inside of the first storage unit 133 and pressurizes the inside of the second storage unit 135. The drive mechanism 126 may also include a decompression flow path 148 that connects the inside of the first storage unit 133 to the pressure variable mechanism 147 and a pressure sensor 149 that can detect the pressure in the decompression flow path 148. The drive mechanism 126 may also include an atmospheric open path 150 connected to the first storage unit 133 and a pressurization flow path 151 that connects the inside of the second storage unit 135 to the pressure variable mechanism 147.

[0180] The drive mechanism 126 may also include an air chamber 153 separated from the liquid chamber 141 by a flexible member 142, a spring 154 disposed in the air chamber 153, and an air flow path 155 connected to the air chamber 153. The spring 154 presses the flexible member 142 to reduce pressure fluctuations of the liquid in the recovery flow path 139 and the liquid ejection head 123.

[0181] The pressure variable mechanism 147 is, for example, a tube pump that sends out air by rotating the tube edge while crimping the tube edge. One end of a tube (not shown) of the pressure variable mechanism 147 is connected to the decompression flow path 148 and the air flow path 155, and the other end is connected to the pressurization flow path 151. By driving the pressure variable mechanism 147 to rotate forward, the air introduced from the decompression flow path 148 and the air flow path 155 is sent to the pressurization flow path 151. By driving the pressure variable mechanism 147 to rotate in reverse, the air introduced from the pressurization flow path 151 is sent to the decompression flow path 148 and the air flow path 155.

[0182] In the present embodiment, a pressurization mechanism 157 is constituted by including the pressure variable mechanism 147, the air chamber 153, and the air flow path 155 that connects the pressure variable mechanism 147 and the air chamber 153, and a micro-pressurization unit 158 is constituted by adding the liquid chamber 141 to the pressurization mechanism 157. The micro-pressurization unit 158 has the liquid chamber 141 and the pressurization mechanism 157 that can pressurize the flexible member 142 from the outside of the liquid chamber 141. The micro-pressurization unit 158 is provided in the recovery flow path 139 between the liquid ejection head 123 and the third valve 140 to pressurize the liquid in the recovery flow path 139.

[0183] Next, the first storage unit 133 will be described.

[0184] The first storage unit 133 may also include a decompression chamber 160 connected to the decompression flow path 148, and a float valve 161 that can open and close the decompression flow path 148. The first storage unit 133 may also include a first storage chamber 162 that stores the liquid, a liquid level sensor 163 that detects the amount of the liquid stored in the first storage chamber 162, and a first gas-liquid separation membrane 164 that separates the first storage chamber 162 from the drive mechanism 126. The first gas-liquid separation membrane 164 is a membrane that has the property of allowing gas to pass through but not allowing liquid to pass through. For example, the first gas-liquid separation membrane 164 may be provided in the first storage chamber 162 to separate the first storage chamber 162 from the atmosphere open path 150. The first gas-liquid separation membrane 164 may be provided in the decompression chamber 160 to separate the first storage chamber 162 from the decompression flow path 148. The first storage unit 133 may also include a sealing member 165 that can seal the space between the decompression chamber 160 and the float valve 161.

[0185] The float valve 161 moves following the movement of the first liquid level 166 in the first storage unit 133. The float valve 161 contacts the sealing member 165 where the height of the first liquid level 166 reaches a specified height, closing the decompression chamber 160. That is, the float valve 161 of the present embodiment closes the decompression flow path 148 by separating the decompression chamber 160 from the first storage chamber 162.

[0186] In the present embodiment, the position of the first liquid level 166 when the float valve 161 closes the decompression flow path 148 is referred to as the standard position. The standard position is a position lower than the nozzle surface 121. The first liquid level 166 varies within a range lower than the nozzle surface 121.

[0187] Specifically, when the first liquid level 166 is below the standard position, the float valve 161 separates from the sealing member 165, and the first storage chamber 162 communicates with the decompression chamber 160. When the pressure variable mechanism 147 decompresses the inside of the decompression chamber 160, the inside of the first storage unit 133 is also decompressed, and liquid is supplied from the liquid storage unit 124 to the first storage unit 133. The first liquid level 166 rises by an amount corresponding to the supplied liquid. When the first liquid level 166 reaches the standard position, the float valve 161 closes the decompression flow path 148. Thereby, the decompression in the first storage chamber 162 stops, and the liquid stops flowing from the liquid storage unit 124 into the first storage unit 133.

[0188] The first liquid level 166 drops due to the supply of liquid from the first storage unit 133 to the second storage unit 135. When the first liquid level 166 drops and the float valve 161 connects the decompression chamber 160 with the first storage chamber 162, liquid is supplied from the liquid storage unit 124 to the first storage unit 133. Therefore, the first liquid level 166 moves below the standard position.

[0189] When the liquid stored in the liquid storage unit 124 runs out, the first liquid level 166 can no longer rise to the standard position. The liquid level sensor 163 can also detect that the first liquid level 166 is at the standard position, the replenishment position below the standard position of the first liquid level 166, and the full position above the standard position of the first liquid level 166. When the first liquid level 166 is at the full position, the first storage unit 133 stores the maximum amount of liquid. The replenishment position is the position used as a reference for replenishing liquid from the liquid storage unit 124 to the first storage unit 133. In the case where the first liquid level 166 does not rise to the standard position even when the inside of the first storage unit 133 is decompressed, the control unit 119 can also determine that the liquid storage unit 124 is empty and instruct the user to replace the liquid storage unit 124 or replenish the liquid in the liquid storage unit 124.

[0190] The standard position of this embodiment is located above the position where the downstream end of the recovery flow path 139 is connected in the first storage chamber 162. Therefore, when the first liquid level 166 is at the standard position, the liquid in the first storage section 133 can be supplied to the liquid ejection head 123 via the recovery flow path 139.

[0191] Next, the second storage section 135 will be described.

[0192] The second storage section 135 may also have a second storage chamber 168 for storing liquid and a second gas-liquid separation membrane 169 that separates the second storage chamber 168 from the pressurization flow path 151. Similar to the first gas-liquid separation membrane 164, the second gas-liquid separation membrane 169 is a membrane having the property of allowing gas to pass through but not allowing liquid to pass through.

[0193] Liquid is supplied from the first storage section 133 to the second storage section 135 due to the head difference. The first valve 136 may also be configured to have a check valve that allows liquid to flow from the first storage section 133 to the second storage section 135 and restricts liquid from flowing from the second storage section 135 to the first storage section 133. When the pressures in the first storage chamber 162 and the second storage chamber 168 are atmospheric pressures, the second liquid level 170 of the liquid in the second storage section 135 becomes the same height as the first liquid level 166. In other words, the second liquid level 170 varies within a range lower than the nozzle surface 121. The liquid in the liquid ejection head 123 is maintained at a negative pressure due to the head difference with the liquid in the first storage section 133 and the second storage section 135. When the liquid is consumed in the liquid ejection head 123, the liquid stored in the second storage section 135 is supplied to the liquid ejection head 123.

[0194] The first valve 136 closes the communication path 134 when the pressure in the second storage section 135 is greater than the pressure in the first storage section 133. Therefore, when the second storage section 135 is pressurized by the pressure variable mechanism 147, the first valve 136 closes the communication path 134. When the first storage section 133 is depressurized by the pressure variable mechanism 147, the first valve 136 closes the communication path 134. The opening and closing of the second valve 138 and the third valve 140 are controlled by the control unit 119. The second valve 138 is arranged to be able to open and close the supply flow path 137 when the pressure variable mechanism 147 performs pressurization.

[0195] The drive mechanism 126 includes a thin tube portion 172 branched from the pressurization flow path 151 and first selection valves 173a to ninth selection valves 173i that can open and close the flow path. The thin tube portion 172 is a tube that is thin enough to greatly restrict the flow of liquid relative to the flow of air and is tortuous.

[0196] The first selection valve 173a opens to connect the decompression flow path 148 and the air flow path 155 to the atmosphere. The second selection valve 173b opens to connect the decompression flow path 148 and the air flow path 155 to the pressure sensor 149. The third selection valve 173c opens to open the air flow path 155 and connect the pressure variable mechanism 147 to the air chamber 153.

[0197] The fourth selection valve 173d opens to open the decompression flow path 148 and connect the pressure variable mechanism 147 to the decompression chamber 160. The fifth selection valve 173e opens to connect the pressurization flow path 151 to the pressure sensor 149. The sixth selection valve 173f opens to connect the pressurization flow path 151 to the atmosphere. The seventh selection valve 173g opens to open the atmosphere opening path 150 and connect the first storage chamber 162 to the atmosphere. The eighth selection valve 173h opens to open the pressurization flow path 151 and connect the pressure variable mechanism 147 to the second storage chamber 168. The ninth selection valve 173i opens to connect the pressurization flow path 151 to the capillary portion 172 and connect the pressurization flow path 151 to the atmosphere via the capillary portion 172.

[0198] When changing the pressure in the air chamber 153, the drive mechanism 126 opens the second selection valve 173b, the third selection valve 173c, and the sixth selection valve 173f and closes the other selection valves. When the pressure variable mechanism 147 is driven to rotate forward in this state, the air in the air chamber 153 is discharged via the air flow path 155 and the pressurization flow path 151, and the pressure in the air chamber 153 decreases. When the pressure variable mechanism 147 is driven to rotate backward in this state, air is sent into the air chamber 153 via the pressurization flow path 151 and the air flow path 155, and the pressure in the air chamber 153 increases. At this time, the pressure sensor 149 can also detect the pressure in the air flow path 155 and the air chamber 153. The control unit 119 can also control the drive of the pressure variable mechanism 147 based on the detection result of the pressure sensor 149.

[0199] When opening the first storage portion 133 to the atmosphere, the drive mechanism 126 opens the seventh selection valve 173g and stops the drive of the pressure variable mechanism 147. The first storage chamber 162 is connected to the atmosphere via the atmosphere opening path 150 and becomes atmospheric pressure.

[0200] When the pressure in the first storage unit 133 is reduced, the drive mechanism 126 opens the second selection valve 173b, the fourth selection valve 173d, and the sixth selection valve 173f, and closes the other selection valves. When the pressure variable mechanism 147 rotates forward in this state, the air in the decompression chamber 160 is discharged through the decompression flow path 148 and the pressurization flow path 151, and the pressure in the decompression chamber 160 decreases. At this time, the pressure sensor 149 can also detect the pressure in the decompression flow path 148 and the decompression chamber 160. The control unit 119 can also control the drive of the pressure variable mechanism 147 based on the detection result of the pressure sensor 149.

[0201] When the second storage unit 135 is opened to the atmosphere, the drive mechanism 126 opens the ninth selection valve 173i and stops the drive of the pressure variable mechanism 147. The second storage chamber 168 communicates with the atmosphere through the pressurization flow path 151 and the capillary portion 172 and becomes atmospheric pressure.

[0202] When the pressure in the second storage unit 135 is increased, the drive mechanism 126 opens the first selection valve 173a, the fifth selection valve 173e, and the eighth selection valve 173h, and closes the other selection valves. When the pressure variable mechanism 147 rotates forward in this state, air flows into the second storage chamber 168 through the pressurization flow path 151, and the pressure in the second storage chamber 168 increases. At this time, the pressure sensor 149 can also detect the pressure in the pressurization flow path 151 and the second storage chamber 168. The control unit 119 can also control the drive of the pressure variable mechanism 147 based on the detection result of the pressure sensor 149.

[0203] Next, with reference to Figures 12 to 18 the flowchart shown, the control method of the liquid ejection device 111 will be described. Here, the step order of each control method can be arbitrarily replaced within the range not departing from the purpose of each control method.

[0204] Figure 12 The overall filling routine shown can also be executed at the timing when the liquid storage unit 124 starts to be installed in the installation unit 128. The overall filling routine can also be executed at the timing when the liquid ejection head 123 is replaced and the liquid storage unit 124 is installed in the installation unit 128. In the initial state, the second valve 138, the third valve 140, and all the selection valves are closed.

[0205] In step S1101, the control unit 119 depressurizes the first storage unit 133. In step S1102, the control unit 119 determines whether the pressure detected by the pressure sensor 149 is less than a specified pressure. The specified pressure is a negative pressure, and it is a negative pressure greater than the negative pressure that allows the liquid to flow from the liquid storage unit 124 into the first storage unit 133 and raise the first liquid level 166. When the detected pressure detected by the pressure sensor 149 is equal to or greater than the specified pressure, step S1102 is NO, and the control unit 119 stands by until the detected pressure is less than the specified pressure. When the detected pressure is less than the specified pressure, step S1102 is YES, and the control unit 119 transfers the process to step S1103.

[0206] In step S1103, the control unit 119 opens the first storage unit 133 to the atmosphere. In step S1104, the control unit 119 opens the second storage unit 135 to the atmosphere. In step S1105, the control unit 119 determines whether a supply time has elapsed since the first storage unit 133 and the second storage unit 135 were opened to the atmosphere. The supply time is the time required to supply the liquid from the first storage unit 133 to the second storage unit 135 to make the heights of the first liquid level 166 and the second liquid level 170 the same. When the supply time has not elapsed, step S1105 is NO, and the control unit 119 stands by until the supply time has elapsed. When the supply time has elapsed, step S1105 is YES, and the control unit 119 transfers the process to step S1106. Here, step S1103 and step S1104 can be performed simultaneously, or step S1103 can be performed after step S1104.

[0207] In step S1106, the control unit 119 opens the second valve 138. In step S1107, the control unit 119 opens the third valve 140. In step S1108, the control unit 119 pressurizes the second storage unit 135. Here, step S1106 and step S1107 can also be performed simultaneously with step S1108 respectively, or can be performed after step S1108.

[0208] In step S1109, the control unit 119 determines whether a first filling time has elapsed since the second storage unit 135 was pressurized. The first filling time is the time required to fill the liquid in the second storage unit 135 into the supply flow path 137 and the recovery flow path 139. When the first filling time has not elapsed, step S1109 is NO, and the control unit 119 stands by until the first filling time has elapsed. When the first filling time has elapsed, step S1109 is YES, and the control unit 119 transfers the process to step S1110.

[0209] In step S1110, the control unit 119 closes the second valve 138. In step S1111, the control unit 119 closes the third valve 140. In step S1112, the control unit 119 opens the second storage unit 135 to the atmosphere. In step S1113, the control unit 119 reduces the pressure in the first storage unit 133. In step S1114, the control unit 119 determines whether the pressure detected by the pressure sensor 149 is less than a specified pressure. When the detected pressure detected by the pressure sensor 149 is equal to or greater than the specified pressure, step S1114 is NO, and the control unit 119 stands by until the detected pressure is less than the specified pressure. When the detected pressure is less than the specified pressure, step S1114 is YES, and the control unit 119 transfers the process to step S1115. Here, step S1110 and step S1111 may also be performed simultaneously with step S1112, or after step S1112.

[0210] In step S1115, the control unit 119 opens the first storage unit 133 to the atmosphere. In step S1116, the control unit 119 determines whether a supply time has elapsed since the first storage unit 133 was opened to the atmosphere. When the supply time has not elapsed, step S1116 is NO, and the control unit 119 stands by until the supply time has elapsed. When the supply time has elapsed, step S1116 is YES, and the control unit 119 transfers the process to step S1117.

[0211] In step S1117, the control unit 119 closes the second valve 138. In step S1118, the control unit 119 pressurizes the second storage unit 135. In step S1119, the control unit 119 determines whether a second filling time has elapsed since the second storage unit 135 was pressurized. The second filling time is the time required to fill the liquid from the supply flow path 137 to the nozzle 122. When the second filling time has not elapsed, step S1119 is NO, and the control unit 119 stands by until the second filling time has elapsed. When the second filling time has elapsed, step S1119 is YES, and the control unit 119 transfers the process to step S1120. Here, step S1117 may also be performed simultaneously with step S1118, or after step S1118.

[0212] In step S1120, the control unit 119 stops driving the pressure variable mechanism 147. In step S1121, the control unit 119 opens the second storage unit 135 to the atmosphere and ends the overall filling routine. Here, step S1120 may also be performed simultaneously with step S1121, or after step S1121.

[0213] Next, the operation during overall filling will be described.

[0214] AsFigure 11 As shown, the liquid ejection device 111 decompresses the inside of the first storage unit 133 through the pressure variable mechanism 147 to supply liquid from the liquid storage unit 124 to the first storage unit 133. At this time, the pressure of the first storage unit 133 is lower than the pressure of the second storage unit 135. Therefore, the first valve 136 closes. That is, the liquid ejection device 111 closes the communication path 134 by using the first valve 136 through decompressing the inside of the first storage unit 133.

[0215] When decompressing the inside of the first storage unit 133, liquid is supplied from the liquid storage unit 124 to the first storage unit 133, and the first liquid level 166 rises. Since the communication path 134 is closed, no liquid is supplied to the second storage unit 135.

[0216] When the first liquid level 166 rises to the standard position, the float valve 161 separates the decompression chamber 160 from the first storage chamber 162. The decompression of the first storage chamber 162 stops, and the liquid stops flowing into the first storage unit 133. The pressure of the decompression chamber 160 closed by the float valve 161 further decreases. When the detected pressure detected by the pressure sensor 149 is less than the specified pressure, the control unit 119 stops the drive of the pressure variable mechanism 147 and opens the first storage unit 133 and the second storage unit 135 to the atmosphere.

[0217] When opening the first storage unit 133 and the second storage unit 135 to the atmosphere, the first valve 136 opens to open the communication path 134. Specifically, the liquid ejection device 111 opens the communication path 134 through the first valve 136, releases the decompression of the inside of the first storage unit 133 by the pressure variable mechanism 147, and supplies the liquid from the first storage unit 133 to the second storage unit 135 using the head difference. The first liquid level 166 drops by an amount corresponding to the liquid supplied to the second storage unit 135. The second liquid level 170 rises by an amount corresponding to the liquid supplied from the first storage unit 133. When the heights of the first liquid level 166 and the second liquid level 170 are the same, the liquid stops flowing from the first storage unit 133 to the second storage unit 135.

[0218] The liquid ejecting device 111 opens the second valve 138 to open the supply flow path 137 through the second valve 138. The liquid ejecting device 111 opens the third valve 140 to open the recovery flow path 139 through the third valve 140. The liquid ejecting device 111 pressurizes the inside of the second storage portion 135 through the pressure variable mechanism 147. At this time, since the pressure of the second storage portion 135 is higher than the pressure of the first storage portion 133, the first valve 136 closes. That is, the liquid ejecting device 111 closes the communication path 134 by using the first valve 136 by pressurizing the second storage portion 135. The liquid in the second storage portion 135 flows into the first storage portion 133 through the supply flow path 137, the liquid ejection head 123, and the recovery flow path 139. In other words, the liquid ejecting device 111 fills the supply flow path 137 and the recovery flow path 139 with the liquid in the second storage portion 135.

[0219] Next, the liquid ejecting device 111 closes the second valve 138 to close the supply flow path 137 through the second valve 138. The liquid ejecting device 111 closes the third valve 140 to close the recovery flow path 139 through the third valve 140. The liquid ejecting device 111 opens the second storage portion 135 to the atmosphere.

[0220] The liquid ejecting device 111 depressurizes the inside of the first storage portion 133 through the pressure variable mechanism 147 to supply liquid from the liquid containing portion 124 to the first storage portion 133. At this time, since the pressure of the first storage portion 133 is lower than the pressure of the second storage portion 135, the first valve 136 closes. That is, the liquid ejecting device 111 closes the communication path 134 by using the first valve 136 by depressurizing the inside of the first storage portion 133.

[0221] When the inside of the first storage portion 133 is depressurized, liquid is supplied from the liquid containing portion 124 to the first storage portion 133, and the first liquid level 166 rises. Since the communication path 134 is closed, no liquid is supplied to the second storage portion 135. When the first liquid level 166 rises to the standard position and the detection pressure detected by the pressure sensor 149 is less than the specified pressure, the control unit 119 stops the drive of the pressure variable mechanism 147 and opens the first storage portion 133 to the atmosphere.

[0222] The second storage unit 135 is first opened to the atmosphere. Therefore, when the first storage unit 133 is opened to the atmosphere, the first valve 136 is opened to open the communication path 134. The liquid ejecting device 111 opens the communication path 134 through the first valve 136, and releases the decompression of the pressure variable mechanism 147 on the inside of the first storage unit 133, and supplies the liquid from the first storage unit 133 to the second storage unit 135 using the head difference. When the heights of the first liquid surface 166 and the second liquid surface 170 are the same, the liquid ejecting device 111 opens the second valve 138 to open the supply flow path 137. At this time, the third valve 140 is closed to close the recovery flow path 139.

[0223] The liquid ejecting device 111 pressurizes the inside of the second storage unit 135 through the pressure variable mechanism 147 in a state where the recovery flow path 139 is closed by the third valve 140. The liquid ejecting device 111 closes the communication path 134 again using the first valve 136 by making the pressure inside the second storage unit 135 higher than the pressure inside the first storage unit 133. Since the recovery flow path 139 is closed, the liquid inside the second storage unit 135 is supplied to the liquid ejection head 123 through the supply flow path 137 and discharged from the nozzle 122. The liquid ejecting device 111 fills the liquid inside the second storage unit 135 into the nozzle 122 of the liquid ejection head 123.

[0224] When filling the liquid into the liquid ejection head 123, the liquid ejecting device 111 may also stop the driving of the pressure variable mechanism 147 and open the second storage unit 135 to the atmosphere. Thereby, the first valve 136 is opened to open the communication path 134. The liquid inside the first storage unit 133 is supplied to the second storage unit 135 through the communication path 134. The liquid ejecting device 111 may also close the second valve 138.

[0225] Figure 13 The illustrated liquid circulation routine can be executed at the timing indicating the execution of the liquid circulation. For example, the execution of the liquid circulation is indicated during the standby period after the overall filling and before printing or the like. The control unit 119 may also execute the liquid circulation routine regularly.

[0226] In step S1201, the control unit 119 opens the second valve 138. In step S1202, the control unit 119 opens the third valve 140. In step S1203, the control unit 119 opens the first storage unit 133 to the atmosphere. In step S1204, the control unit 119 pressurizes the inside of the second storage unit 135. Here, steps S1201 to S1204 may be performed simultaneously or in a swapped order.

[0227] In step S1205, the control unit 119 determines whether the first liquid level 166 is at the full position. If the first liquid level 166 is not at the full position, the answer in step S1205 is no, and the control unit 119 stands by until the first liquid level 166 reaches the full position. When the first liquid level 166 is at the full position, the answer in step S1205 is yes, and the control unit 119 transfers the process to step S1206. In step S1206, the control unit 119 closes the second valve 138. In step S1207, the control unit 119 opens the second storage unit 135 to the atmosphere and ends the liquid circulation routine. Here, step S1206 may be performed simultaneously with step S1207 or after step S1207.

[0228] Next, the operation during liquid circulation will be described.

[0229] As Figure 11 shown, the control unit 119 opens the second valve 138 to open the supply flow path 137 through the second valve 138. The control unit 119 opens the third valve 140 to open the recovery flow path 139 through the third valve 140.

[0230] The liquid ejection device 111 pressurizes the inside of the second storage unit 135 through the pressure variable mechanism 147, so that the liquid flows from the second storage unit 135 to the first storage unit 133 via the liquid ejection head 123. At this time, the pressure in the second storage unit 135 is higher than the pressure in the first storage unit 133. Therefore, the first valve 136 closes. That is, the liquid ejection device 111 pressurizes the inside of the second storage unit 135 to close the communication path 134 by using the first valve 136.

[0231] Figure 14 The printing routine shown can also be executed at the timing of instructing printing.

[0232] In step S1301, the control unit 119 opens the first storage unit 133 to the atmosphere. In step S1302, the control unit 119 opens the second storage unit 135 to the atmosphere. In step S1303, the control unit 119 opens the second valve 138.

[0233] In step S1304, the control unit 119 determines whether the liquid ejection flow rate generated by ejecting the liquid from the nozzle 122 during printing is equal to or greater than the threshold value. The control unit 119 can also calculate the ejection flow rate based on the printing data. If the ejection flow rate is equal to or greater than the threshold value, the answer in step S1304 is yes, and the control unit 119 transfers the process to step S1305. In step S1305, the control unit 119 opens the third valve 140.

[0234] In step S1304, when the ejection flow rate is less than the threshold value, step S1304 is NO, and the control unit 119 transfers the process to step S1306. In step S1306, the control unit 119 closes the third valve 140. In step S1307, the control unit 119 executes printing and ends the printing routine.

[0235] Here, step S1301 and step S1302 can be performed simultaneously with step S1303 or after step S1303, can be performed simultaneously with step S1305 or after step S1305, and can also be performed simultaneously with step S1306 or after step S1306.

[0236] Next, the operation during the execution of the printing routine will be described.

[0237] As Figure 11 shown, when the ejection flow rate when the liquid ejection head 123 ejects liquid onto the medium 112 is less than the threshold value, the control unit 119 opens the second valve 138 and closes the third valve 140. That is, the control unit 119 executes printing in a state where the supply flow path 137 is opened by the second valve 138 and the recovery flow path 139 is closed by the third valve 140. Therefore, liquid is supplied from the second storage unit 135 to the liquid ejection head 123 via the supply flow path 137.

[0238] When the ejection flow rate when the liquid ejection head 123 ejects liquid onto the medium 112 is equal to or greater than the threshold value, the control unit 119 opens the second valve 138 and the third valve 140. That is, the control unit 119 executes printing in a state where the supply flow path 137 is opened by the second valve 138 and the recovery flow path 139 is opened by the third valve 140. Therefore, liquid is supplied from the second storage unit 135 to the liquid ejection head 123 via the supply flow path 137, and liquid is also supplied from the first storage unit 133 to the liquid ejection head 123 via the recovery flow path 139.

[0239] Figure 15 The pressurized discharge routine shown is executed when pressurized discharge is instructed, when an ejection failure occurs where liquid cannot be normally ejected from the nozzle 122, etc.

[0240] In step S1401, the control unit 119 decompresses the inside of the first storage unit 133. In step S1402, the control unit 119 determines whether the pressure detected by the pressure sensor 149 is less than the specified pressure. When the detected pressure detected by the pressure sensor 149 is equal to or greater than the specified pressure, step S1402 is NO, and the control unit 119 stands by until the detected pressure is less than the specified pressure. When the detected pressure is less than the specified pressure, step S1402 is YES, and the control unit 119 transfers the process to step S1403.

[0241] In step S1403, the control unit 119 opens the first storage unit 133 to the atmosphere. In step S1404, the control unit 119 opens the second storage unit 135 to the atmosphere. In step S1405, the control unit 119 determines whether the supply time has elapsed since the first storage unit 133 and the second storage unit 135 were opened to the atmosphere. If the supply time has not elapsed, step S1405 is NO, and the control unit 119 stands by until the supply time has elapsed. When the supply time has elapsed, step S1405 is YES, and the control unit 119 transfers the process to step S1406. Here, step S1403 and step S1404 may be performed simultaneously, or step S1403 may be performed after step S1404.

[0242] In step S1406, the control unit 119 opens the second valve 138. In step S1407, the control unit 119 closes the third valve 140. In step S1408, the control unit 119 pressurizes the inside of the second storage unit 135. In step S1409, the control unit 119 determines whether the pressurization discharge time has elapsed since the inside of the second storage unit 135 was pressurized. The pressurization discharge time is the time required for the pressure applied to the second storage unit 135 to be transmitted through the supply flow path 137 to the nozzle 122 to discharge the liquid from the nozzle 122 and restore the state of the nozzle 122. Here, step S1406 and step S1407 may also be performed simultaneously with step S1408, or may be performed after step S1408.

[0243] Before the pressurization discharge time has elapsed, step S1409 is NO, and the control unit 119 stands by until the pressurization discharge time has elapsed. When the pressurization discharge time has elapsed, step S1409 is YES, and the control unit 119 transfers the process to step S1410. In step S1410, the control unit 119 closes the second valve 138. In step S1411, the control unit 119 opens the second storage unit 135 to the atmosphere and ends the pressurization discharge routine. Here, step S1410 may be performed simultaneously with step S1411, or may be performed after step S1411.

[0244] Next, the operation during pressurization discharge will be described.

[0245] As Figure 11As shown, the liquid ejecting device 111 decompresses the inside of the first storage unit 133 through the pressure variable mechanism 147. The liquid ejecting device 111 closes the first valve 136 and shuts off the communication path 134 by making the pressure inside the first storage unit 133 lower than the pressure inside the second storage unit 135. The liquid ejecting device 111 decompresses the inside of the first storage unit 133 to supply liquid from the liquid storage unit 124 to the first storage unit 133. Since the communication path 134 is closed, liquid is supplied to the first storage unit 133, and the first liquid level 166 rises without supplying liquid to the second storage unit 135.

[0246] When the first liquid level 166 rises to the standard position and the float valve 161 separates the decompression chamber 160 from the first storage chamber 162, the detected pressure detected by the pressure sensor 149 is less than the specified pressure. The liquid ejecting device 111 can also cancel the decompression of the inside of the first storage unit 133 by the pressure variable mechanism 147 when the pressure detected by the pressure sensor 149 is less than the specified pressure when decompressing the inside of the first storage unit 133 through the pressure variable mechanism 147. The liquid ejecting device 111 stops driving the pressure variable mechanism 147 and opens the first storage unit 133 and the second storage unit 135 to the atmosphere.

[0247] When the first storage unit 133 and the second storage unit 135 are opened to the atmosphere, the first valve 136 opens and the communication path 134 is opened. Therefore, the liquid ejecting device 111 opens the communication path 134 through the first valve 136, cancels the decompression of the inside of the first storage unit 133 by the pressure variable mechanism 147, and supplies liquid from the first storage unit 133 to the second storage unit 135 using the head difference. When the heights of the first liquid level 166 and the second liquid level 170 are the same, the liquid ejecting device 111 opens the second valve 138 and opens the supply flow path 137. At this time, the third valve 140 closes and shuts off the recovery flow path 139.

[0248] The liquid ejecting device 111 pressurizes the inside of the second storage unit 135 through the pressure variable mechanism 147 and discharges liquid from the nozzle 122. That is, the liquid ejecting device 111 closes the communication path 134 again using the first valve 136 by making the pressure inside the second storage unit 135 higher than the pressure inside the first storage unit 133. The liquid inside the second storage unit 135 is supplied to the liquid ejecting head 123 through the supply flow path 137 and is discharged from the nozzle 122 because the recovery flow path 139 is closed.

[0249] Figure 16 The pressure accumulation discharge routine shown can also be executed in cases such as when an instruction to execute pressure accumulation discharge is given, or when the ejection failure is not improved even when pressure accumulation discharge is executed.

[0250] In step S1501, the control unit 119 decompresses the first storage unit 133. In step S1502, the control unit 119 determines whether the pressure detected by the pressure sensor 149 is less than a specified pressure. When the detected pressure detected by the pressure sensor 149 is equal to or greater than the specified pressure, step S1502 is NO, and the control unit 119 stands by until the detected pressure is less than the specified pressure. When the detected pressure is less than the specified pressure, step S1502 is YES, and the control unit 119 transfers the process to step S1503.

[0251] In step S1503, the control unit 119 opens the first storage unit 133 to the atmosphere. In step S1504, the control unit 119 opens the second storage unit 135 to the atmosphere. In step S1506, the control unit 119 closes the second valve 138. In step S1507, the control unit 119 closes the third valve 140. In step S1508, the control unit 119 determines whether to instruct the execution of the first pressure accumulation discharge during the pressure accumulation discharge or to instruct the execution of the second pressure accumulation discharge in which the accumulated pressure is less than the first pressure accumulation discharge. When the first pressure accumulation discharge is to be executed, step S1508 is YES, and the control unit 119 transfers the process to step S1509. In step S1509, the control unit 119 sets the pressure accumulation time to the first time.

[0252] In step S1508, when the second pressure accumulation discharge is to be executed, step S1508 is NO, and the control unit 119 transfers the process to step S1510. In step S1510, the control unit 119 sets the pressure accumulation time to a second time shorter than the first time.

[0253] In step S1511, the control unit 119 pressurizes the second storage unit 135. In step S1512, the control unit 119 determines whether the pressure accumulation time, which is an example of a specified time, has elapsed since the start of pressurizing the second storage unit 135. When the pressure accumulation time has not elapsed, step S1512 is NO, and the control unit 119 stands by until the pressure accumulation time has elapsed. When the pressure accumulation time has elapsed, step S1512 is YES, and the control unit 119 transfers the process to step S1513.

[0254] In step S1513, the control unit 119 opens the second valve 138. In step S1514, the control unit 119 determines whether the pressure accumulation discharge time has elapsed since the second valve 138 was opened. The pressure accumulation discharge time is the time required for the pressure accumulated in the second storage unit 135 to be transmitted to the nozzle 122 via the supply flow path 137 and for the liquid to be discharged from the nozzle 122.

[0255] Before the pressure accumulation discharge time has elapsed, step S1514 is NO, and the control unit 119 stands by until the pressure accumulation discharge time has elapsed. When the pressure accumulation discharge time has elapsed, step S1514 is YES, and the control unit 119 transfers the process to step S1515. In step S1515, the control unit 119 closes the second valve 138. In step S1516, the control unit 119 opens the second storage unit 135 to the atmosphere and ends the pressure accumulation discharge routine.

[0256] Here, step S1506 and step S1507 may also be performed simultaneously with the start of pressurization in step S1511, or may be performed just after the start of pressurization in step S1511. In addition, step S1515 may be performed simultaneously with step S1516, or may be performed after step S1516. In addition, step S1515 may not be performed.

[0257] Next, the operation during pressure accumulation discharge will be described.

[0258] As Figure 11 shown, the liquid ejection device 111 decompresses the inside of the first storage unit 133 through the pressure variable mechanism 147. The liquid ejection device 111 closes the first valve 136 by making the pressure inside the first storage unit 133 lower than the pressure inside the second storage unit 135, and closes the communication path 134 using the first valve 136. The liquid ejection device 111 decompresses the inside of the first storage unit 133 to supply liquid from the liquid accommodation unit 124 to the first storage unit 133. Since the communication path 134 is closed, liquid is supplied to the first storage unit 133, and the first liquid level 166 rises without supplying liquid to the second storage unit 135.

[0259] When the first liquid level 166 rises to the standard position and the float valve 161 separates the decompression chamber 160 from the first storage chamber 162, the detected pressure detected by the pressure sensor 149 is less than the specified pressure. The liquid ejection device 111 may also cancel the decompression of the inside of the first storage unit 133 by the pressure variable mechanism 147 when the pressure detected by the pressure sensor 149 is less than the specified pressure during the decompression of the inside of the first storage unit 133 by the pressure variable mechanism 147. The liquid ejection device 111 stops driving the pressure variable mechanism 147 and opens the first storage unit 133 and the second storage unit 135 to the atmosphere.

[0260] When the first storage unit 133 and the second storage unit 135 are opened to the atmosphere, the first valve 136 opens and the communication path 134 is opened. The liquid ejection device 111 opens the communication path 134 through the first valve 136, cancels the decompression of the inside of the first storage unit 133 by the pressure variable mechanism 147, and supplies liquid from the first storage unit 133 to the second storage unit 135 using the head difference.

[0261] The liquid ejecting device 111 closes the second valve 138 and shuts off the supply flow path 137 through the second valve 138. The liquid ejecting device 111 closes the third valve 140 and shuts off the recovery flow path 139 through the third valve 140. The liquid ejecting device 111 pressurizes the interior of the second storage portion 135 through the pressure variable mechanism 147. The liquid ejecting device 111 closes the first valve 136 by making the pressure inside the second storage portion 135 higher than the pressure inside the first storage portion 133, and closes the communication path 134 again using the first valve 136. In a state where the communication path 134 and the supply flow path 137 are closed, the liquid ejecting device 111 pressurizes the interior of the second storage portion 135 through the pressure variable mechanism 147 for a pressure accumulation time.

[0262] The magnitude of the pressure accumulated in the second storage portion 135 is proportional to the time for which the interior of the second storage portion 135 is pressurized in a state where the communication path 134 and the supply flow path 137 are closed. In the first pressure accumulation discharge, the time for which the interior of the second storage portion 135 is pressurized by the pressure variable mechanism 147 is the first time. In the second pressure accumulation discharge, the time for which the interior of the second storage portion 135 is pressurized by the pressure variable mechanism 147 is the second time, which is shorter than the first time. The pressure accumulated by the first pressure accumulation discharge is greater than the pressure accumulated by the second pressure accumulation discharge. That is, in the first pressure accumulation discharge, when the interior of the second storage portion 135 is pressurized at the first pressure, the supply flow path 137 is opened through the second valve 138. In the second pressure accumulation discharge, when the interior of the second storage portion 135 is pressurized at the second pressure, which is lower than the first pressure, the supply flow path 137 is opened through the second valve 138.

[0263] When the pressure accumulation discharge time has elapsed since the interior of the second storage portion 135 was pressurized, the liquid ejecting device 111 opens the second valve 138, opens the supply flow path 137 through the second valve 138, and discharges the liquid from the nozzle 122.

[0264] Figure 17 The micro pressure discharge routine shown can also be executed when micro pressure discharge is instructed.

[0265] In step S1601, the control unit 119 opens the second valve 138. In step S1602, the control unit 119 opens the third valve 140. In step S1603, the control unit 119 depressurizes the air chamber 153. In step S1604, the control unit 119 determines whether the depressurization time has elapsed since the air chamber 153 was depressurized. The depressurization time is the time required to deform the flexible member 142 to maximize the volume of the liquid chamber 141.

[0266] Before the decompression time has elapsed, the answer in step S1604 is no, and the control unit 119 stands by until the decompression time has elapsed. When the decompression time has elapsed, the answer in step S1604 is yes, and the control unit 119 transfers the process to step S1605. In step S1605, the control unit 119 closes the second valve 138. In step S1606, the control unit 119 closes the third valve 140. In step S1607, the control unit 119 pressurizes the air chamber 153.

[0267] In step S1608, the control unit 119 determines whether the micro-pressurization time has elapsed since the air chamber 153 was pressurized. The micro-pressurization time is the time required for the pressure of the pressurized air chamber 153 to be transmitted to the nozzle 122 via the liquid chamber 141 and the recovery flow path 139.

[0268] Before the micro-pressurization time has elapsed, the answer in step S1608 is no, and the control unit 119 stands by until the micro-pressurization time has elapsed. When the micro-pressurization time has elapsed, the answer in step S1608 is yes, and the control unit 119 transfers the process to step S1609. In step S1609, the control unit 119 opens the air chamber 153 to the atmosphere and ends the micro-pressurization discharge routine.

[0269] Here, step S1601 and step S1602 may also be performed simultaneously with step S1603, respectively, or after step S1603. In addition, step S1605 and step S1606 may be performed respectively while step S1603 is in progress, may be performed simultaneously with the end of step S1603, or may be performed after step S1603 ends. In addition, step S1605 and step S1606 may also be performed simultaneously with step S1607, respectively, or after step S1607.

[0270] Next, the operation during micro-pressurization discharge will be described.

[0271] As Figure 11 shown, the control unit 119 opens the supply flow path 137 and the recovery flow path 139 by opening the second valve 138 and the third valve 140. The control unit 119 decompresses the air chamber 153, deforms the flexible member 142, and increases the volume of the liquid chamber 141. The liquid flows from the first storage unit 133 into the liquid chamber 141 via the recovery flow path 139, and the liquid flows from the second storage unit 135 into the liquid chamber 141 via the supply flow path 137 and the recovery flow path 139.

[0272] When the volume of the liquid chamber 141 reaches the maximum, the control unit 119 closes the second valve 138 to close the supply flow path 137 through the second valve 138. The control unit 119 closes the third valve 140 to close the recovery flow path 139 through the third valve 140. In this state, the liquid ejecting device 111 supplies pressurized air to the air chamber 153 through the pressure variable mechanism 147, thereby pressurizing the flexible member 142. That is, the liquid ejecting device 111 pressurizes the flexible member 142 through the pressurizing mechanism 157 to discharge the liquid from the nozzle 122. The pressurizing mechanism 157 pressurizes the liquid chamber 141 with a pressure that breaks the meniscus formed in the nozzle 122. The amount of liquid discharged from the liquid ejecting head 123 by micro pressurization discharge is less than the amount of liquid discharged from the liquid ejecting head 123 by pressurization discharge.

[0273] Figure 18 The head replacement routine shown can also be executed when replacing the liquid ejecting head 123.

[0274] In step S1701, the control unit 119 determines whether the liquid containing portion 124 has been removed from the mounting portion 128. When the liquid containing portion 124 is mounted on the mounting portion 128, step S1701 is NO, and the control unit 119 waits until the liquid containing portion 124 is removed. When the liquid containing portion 124 is removed, step S1701 is YES, and the control unit 119 transfers the process to step S1702.

[0275] In step S1702, the control unit 119 opens the second valve 138. In step S1703, the control unit 119 closes the third valve 140. In step S1704, the control unit 119 pressurizes the inside of the second storage portion 135. In step S1705, the control unit 119 determines whether the first discharge time has elapsed since the inside of the second storage portion 135 was pressurized. The first discharge time is the time required to discharge the liquid stored in the second storage portion 135 through the supply flow path 137 and the liquid ejecting head 123.

[0276] Before the first discharge time elapses, step S1705 is NO, and the control unit 119 waits until the first discharge time elapses. When the first discharge time elapses, step S1705 is YES, and the control unit 119 transfers the process to step S1706. In step S1706, the control unit 119 opens the third valve 140.

[0277] In step S1707, the control unit 119 determines whether the second discharge time has elapsed since the third valve 140 was opened. The second discharge time is the time required to recover the liquid in the recovery flow path 139 to the first storage portion 133.

[0278] Before the second discharge time has elapsed, step S1707 is NO, and the control unit 119 stands by until the second discharge time has elapsed. When the second discharge time has elapsed, step S1707 is YES, and the control unit 119 transfers the process to step S1708. In step S1708, the control unit 119 closes the second valve 138. In step S1709, the control unit 119 closes the third valve 140.

[0279] In step S1710, the control unit 119 opens the second storage unit 135 to the atmosphere. In step S1711, the control unit 119 determines whether the liquid ejection head 123 has been replaced. If the liquid ejection head 123 has not been replaced, step S1711 is NO, and the control unit 119 stands by until the liquid ejection head 123 is replaced. When the liquid ejection head 123 has been replaced, step S1711 is YES, and the control unit 119 ends the head replacement routine.

[0280] Here, step S1702 and step S1703 may also be performed simultaneously with the start of pressurization in step S1704, or may be performed after the start of pressurization in step S1704. In addition, step S1708 and step S1709 may also be performed simultaneously with step S1710, or may be performed after step S1710.

[0281] Next, the head replacement routine will be described.

[0282] As Figure 11 shown, when replacing the liquid ejection head 123, the operator executes the head replacement routine and removes the liquid storage unit 124 from the mounting unit 128. Subsequently, the control unit 119 opens the second valve 138 to open the supply flow path 137 through the second valve 138. The control unit 119 closes the third valve 140 to close the recovery flow path 139 through the third valve 140. In this state, the control unit 119 pressurizes the inside of the second storage unit 135.

[0283] Specifically, the liquid ejection device 111 pressurizes the inside of the second storage unit 135 through the pressure variable mechanism 147, and discharges the liquid from the second storage unit 135 to the liquid ejection head 123 from the nozzle 122. At this time, since the pressure of the second storage unit 135 is higher than the pressure of the first storage unit 133, the first valve 136 closes. That is, the liquid ejection device 111 closes the communication path 134 by pressurizing the second storage unit 135, using the first valve 136.

[0284] When discharging the liquid in the second storage unit 135, the supply flow path 137, and the liquid ejection head 123, the control unit 119 opens the third valve 140 to open the recovery flow path 139 through the third valve 140. That is, the liquid ejection device 111 pressurizes the inside of the second storage unit 135 through the pressure variable mechanism 147, and recovers the liquid in the recovery flow path 139 into the first storage unit 133. The operator replaces the liquid ejection head 123 in a state where the liquid has been removed from the supply flow path 137, the liquid ejection head 123, and the recovery flow path 139.

[0285] The effects of the present embodiment will be described.

[0286] (1) A communication path 134 communicating with the first storage unit 133 and a supply flow path 137 communicating with the liquid ejection head 123 are connected to the second storage unit 135. The communication path 134 can be closed by the first valve 136 when the pressure variable mechanism 147 pressurizes the inside of the second storage unit 135. Therefore, the liquid in the pressurized second storage unit 135 is supplied to the liquid ejection head 123 via the supply flow path 137. Therefore, by pressurizing the liquid in the liquid ejection head 123, the liquid can be discharged from the nozzle 122, and the possibility of the liquid ejection head 123 sucking the liquid from the nozzle 122 can be reduced.

[0287] (2) When the first storage unit 133 is depressurized by the pressure variable mechanism 147, the liquid is supplied from the liquid storage unit 124 to the first storage unit 133. When the liquid level height in the first storage unit 133 reaches a specified height, the float valve 161 closes the decompression flow path 148 and stops the decompression in the first storage unit 133. Therefore, the possibility of the liquid overflowing from the first storage unit 133 can be reduced.

[0288] (3) When the pressure variable mechanism 147 pressurizes the inside of the second storage unit 135 in a state where the first valve 136 closes the communication path 134 and the second valve 138 closes the supply flow path 137, the pressing force is accumulated in the second storage unit 135. Therefore, by opening the second valve 138 in a state where the pressure in the second storage unit 135 is increased, a high pressure can be transmitted to the liquid ejection head 123, and for example, a thick liquid or the like can be easily discharged.

[0289] (4) When the pressure variable mechanism 147 pressurizes the inside of the second storage unit 135 with the third valve 140 closed, the liquid is discharged from the liquid ejection head 123. When the pressure variable mechanism 147 pressurizes the inside of the second storage unit 135 with the third valve 140 open, the liquid in the liquid ejection head 123 is recovered into the first storage unit 133 through the recovery flow path 139. Therefore, for example, maintenance can be selected according to the state of the bubbles in the supply flow path 137 and the state of the nozzle 122.

[0290] (5) For example, when driving the first valve 136 to close the communication path 134, a driving source for driving the first valve 136 is required. In this regard, the first valve 136 has a check valve. Specifically, the first valve 136 allows the liquid supplied from the first storage unit 133 to the second storage unit 135 due to the head difference to flow, and restricts the liquid from flowing from the second storage unit 135 to the first storage unit 133 when the liquid in the second storage unit 135 is pressurized. Therefore, the first valve 136 does not require driving, and the driving source can be reduced.

[0291] (6) Regarding the pressurized discharge, the liquid is sequentially supplied from the liquid containing portion 124 to the first storage unit 133, from the first storage unit 133 to the second storage unit 135, and from the second storage unit 135 to the liquid ejection head 123, and the liquid is discharged from the nozzle 122 provided in the liquid ejection head 123. The liquid in the second storage unit 135 is pressurized by the pressure variable mechanism 147 in a state where the communication path 134 is closed, and thus is supplied to the liquid ejection head 123 via the supply flow path 137. Therefore, the liquid ejection device 111 can discharge the liquid from the nozzle 122 by pressurizing the liquid in the liquid ejection head 123, and can reduce the possibility of the liquid ejection head 123 sucking the liquid from the nozzle 122.

[0292] (7) When the pressure detected by the pressure sensor 149 is less than the specified pressure, the pressure variable mechanism 147 releases the decompression in the first storage unit 133. Therefore, for example, even when the float valve 161 is deviated or the like and the float valve 161 cannot close the decompression flow path 148, the possibility of the liquid overflowing from the first storage unit 133 can be reduced.

[0293] (8) For the pressure accumulation discharge, the pressure variable mechanism 147 pressurizes the inside of the second storage unit 135 in a state where the first valve 136 closes the communication path 134 and the second valve 138 closes the supply flow path 137, so that the pressure is accumulated in the second storage unit 135. After pressurizing the inside of the second storage unit 135 in the pressure accumulation discharge, the supply flow path 137 is opened by the second valve 138, so that the accumulated high pressure can be transmitted to the liquid ejection head 123, and for example, a thick liquid or the like can be easily discharged.

[0294] (9) For the overall filling, by combining the opening and closing of the first valve 136, the second valve 138, and the third valve 140 and the driving of the pressure variable mechanism 147, the liquid is supplied from the liquid containing portion 124 to the first storage unit 133, and the liquid can be filled into the second storage unit 135, the supply flow path 137, the liquid ejection head 123, and the recovery flow path 139. Therefore, by performing the overall filling, the liquid can be filled into the entire flow path.

[0295] This embodiment can be modified and implemented as follows. This embodiment and the following modification examples can be implemented in combination with each other within the scope where there is no technical contradiction.

[0296] The liquid ejection device 111 may also include a wiping member (not shown) for wiping the nozzle surface 121. The liquid ejection device 111 may wipe the nozzle surface 121 with the wiping member after discharging the liquid from the nozzle 122. The liquid ejection device 111 may wipe the nozzle surface 121 before the operator removes the liquid ejection head 123.

[0297] The control unit 119 may also control the opening and closing of the first valve 136. The control unit 119 may close the communication path 134 through the first valve 136 before decompressing the first storage unit 133 and before pressurizing the second storage unit 135.

[0298] The second pressure accumulation discharge may also be performed by pressurizing the inside of the second storage unit 135 for a first time with the first valve 136 and the second valve 138 closed to make the pressure inside the second storage unit 135 the first pressure, then opening the first valve 136 to reduce the pressure inside the second storage unit 135 to the second pressure, and then opening the second valve 138.

[0299] The micro pressurization discharge may also pressurize the liquid in the liquid chamber 141 by pressing the flexible member 142 with the spring 154. In this case, the control unit 119 decompresses the air chamber 153 to increase the volume of the liquid chamber 141, and then opens the air chamber 153 to the atmosphere. When the air chamber 153 becomes atmospheric pressure, the spring 154 presses the liquid in the liquid chamber 141, and the liquid is discharged from the liquid ejection head 123. In the case of the structure in which the spring 154 presses the flexible member 142, the spring 154 is included in the pressurization mechanism 157.

[0300] The liquid ejection device 111 may also perform printing in a state where the recovery flow path 139 is opened by the third valve 140 regardless of the ejection flow rate.

[0301] The liquid ejection head 123 may also have a plurality of pressure chambers individually communicating with the plurality of nozzles 122, a common liquid chamber communicating with the plurality of pressure chambers, and a filter chamber accommodating a filter. The first connection portion 144 and the second connection portion 145 are connected to at least one of the pressure chamber, the common liquid chamber, and the filter chamber. For example, when the first connection portion 144 and the second connection portion 145 are connected to the filter chamber, the liquid ejection device 111 may recycle the liquid and recover the bubbles captured by the filter into the first storage unit 133. The liquid ejection device 111 may also perform liquid circulation when bubbles are generated inside the liquid ejection head 123.

[0302] When the liquid ejecting device 111 is on standby or the power is turned off, the second valve 138 and the third valve 140 can also be closed to close the supply flow path 137 and the recovery flow path 139. By closing the supply flow path 137 and the recovery flow path 139, for example, even when the liquid ejecting device 111 is subjected to vibration or impact, the possibility of liquid leakage from the liquid ejection head 123 can be reduced.

[0303] The amount of liquid that the second storage unit 135 can store can also be less than the amount of liquid required for pressure discharge. In this case, the control unit 119 can also alternately execute: pressurizing the inside of the second storage unit 135 to supply liquid from the second storage unit 135 to the liquid ejection head 123; and opening the second storage unit 135 to the atmosphere to supply liquid from the first storage unit 133 to the second storage unit 135.

[0304] The amount of liquid stored in the second storage unit 135 when the first liquid level 166 and the second liquid level 170 are in the replenishment position can also be greater than the amount required for printing during the supply of liquid from the liquid storage unit 124 to the first storage unit 133. Thus, printing can also be continued during the supply of liquid from the liquid storage unit 124 to the first storage unit 133.

[0305] The amount of liquid contained in the liquid storage unit 124 can also be less than the amount of liquid that the supply mechanism 125 can hold. In this case, the liquid storage unit 124 can also be replaced midway during the overall filling of the supply mechanism 125 with liquid.

[0306] For pressure accumulation discharge, after pressurizing the inside of the second storage unit 135 in a state where the communication path 134 is closed by the first valve 136 and the supply flow path 137 is closed by the second valve 138, when the pressure sensor 149 detects that a predetermined pressure is reached, the supply flow path 137 can be opened by the second valve 138. At this time, the control unit 119 can also perform: a first pressure accumulation discharge in which the supply flow path 137 is opened when the pressure sensor 149 detects that the first pressure is reached; and a second pressure accumulation discharge in which the supply flow path 137 is opened when it is detected that the second pressure smaller than the first pressure is reached. The first pressure and the second pressure are greater than the pressure for pressurizing the second storage unit 135 during pressure discharge.

[0307] When the control unit 119 causes the liquid to flow from the recovery flow path 139 into the first storage unit 133, the control unit 119 can also depressurize the inside of the first storage unit 133.

[0308] The control unit 119 can also remove bubbles from the liquid by expanding the bubbles contained in the liquid stored in the first storage unit 133 by depressurizing the inside of the first storage unit 133.

[0309] The liquid ejecting device 111 may also perform decompression in the first storage unit 133 and pressurization in the second storage unit 135 simultaneously. Specifically, the liquid ejecting device 111 may also open the fourth selection valve 173d and the eighth selection valve 173h, close the other selection valves, and drive the pressure variable mechanism 147 to rotate forward. At this time, the liquid ejecting device 111 may also open the second selection valve 173b and cause the pressure sensor 149 to detect the pressure in the decompression flow path 148. The liquid ejecting device 111 may also open the fifth selection valve 173e and cause the pressure sensor 149 to detect the pressure in the pressurization flow path 151.

[0310] It is also possible to make the flow path resistance when the liquid moves in the decompression chamber 160 and the decompression flow path 148 greater than the flow path resistance when the first liquid level 166 rises in the first storage chamber 162. The specified pressure as the standard for relieving the decompression in the first storage unit 133 when decompressing the first storage unit 133 may also be a negative pressure, which is greater than the negative pressure for raising the first liquid level 166 in the first storage chamber 162 and smaller than the negative pressure for moving the liquid in the decompression chamber 160 or the decompression flow path 148.

[0311] The liquid ejecting device 111 may also relieve the decompression in the first storage unit 133 when the first liquid level 166 is detected by the liquid amount sensor 163 to be at the standard position.

[0312] The liquid ejecting device 111 may also relieve the decompression in the first storage unit 133 by opening the first selection valve 173a to connect the decompression flow path 148 to the atmosphere. In this case, the pressure variable mechanism 147 may also continue to be driven.

[0313] Overall filling, pressurized discharge, micro-pressurized discharge, and liquid circulation may be performed multiple times or may be combined. In the case where the amount of liquid that the first storage unit 133 can store is less than the amount of liquid filled in the supply flow path 137, the recovery flow path 139, and the liquid ejection head 123, the supply flow path 137, the recovery flow path 139, and the liquid ejection head 123 may also be filled with liquid by performing overall filling multiple times. For example, micro-pressurized discharge may also be performed after overall filling. By combining overall filling and micro-pressurized discharge, the occurrence of ejection failures can be reduced compared to the case of only performing overall filling.

[0314] The first storage unit 133 and the second storage unit 135 may also be integrally formed.

[0315] The flexible member 142 may also be formed of a rubber film, an elastomeric film, a thin film, or the like.

[0316] The liquid chamber 141 may also be provided in the supply flow path 137. The pressurizing mechanism 157 may also pressurize the liquid chamber provided in the supply flow path 137.

[0317] The pressure variable mechanism 147 can also use a diaphragm pump, a piston pump, a gear pump, etc.

[0318] The liquid ejection head 123 can also eject liquid in a horizontal posture with the nozzle surface 121 being horizontal to perform printing on the medium 112. The liquid ejection head 123 can also be configured to be able to change its posture between a horizontal posture and an inclined posture.

[0319] The liquid ejection device 111 can also include an atmosphere opening path that opens the second storage unit 135 to the atmosphere separately from the pressure application flow path 151.

[0320] In Figure 18 In the head replacement routine shown, the control unit 119 can also execute steps S1702 to S1705 again after executing step S1710. Thereby, the liquid recovered in the first storage unit 133 can be discharged from the liquid ejection head 123.

[0321] The liquid ejection device 11 and the liquid ejection device 111 can also be liquid ejection devices that eject liquids other than ink. The state of the liquid ejected as minute droplets from the liquid ejection device also includes states such as granular, teardrop-shaped, and linear trailing. The liquid here only needs to be a material that can be ejected from the liquid ejection device. For example, the liquid only needs to be in a liquid phase state, including highly viscous or low-viscosity liquid substances, sols, gels, water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals, molten metal fluids, etc. The liquid includes not only liquids as a state of matter but also substances in which solid substances such as pigments and metal particles are dissolved, dispersed, or mixed in a solvent. As a representative example of the liquid, ink, liquid crystal, etc. as described in the above embodiments can be cited. Here, the ink includes various liquid compositions such as ordinary aqueous ink, oil-based ink, gel ink, and hot melt ink. As a specific example of the liquid ejection device, for example, there is a device that ejects a liquid containing materials such as electrode materials and color materials used in the manufacture of liquid crystal displays, electroluminescent displays, surface light-emitting displays, and color filters in a dispersed or dissolved form. The liquid ejection device can also be a device that ejects biological organic substances for manufacturing biochips, a device that serves as a precision pipette and ejects a liquid as a sample, a printing and dyeing device, a micro dispenser, etc. The liquid ejection device can also be a device that precisely ejects lubricating oil for precision machinery such as watches and cameras, a device that ejects a transparent resin liquid such as ultraviolet curable resin onto a substrate to form a minute hemispherical lens, an optical lens, etc. used in optical communication elements, etc. The liquid ejection device can also be a device that ejects an etching liquid such as an acid or a base for etching a substrate, etc.

[0322] Hereinafter, the technical ideas and their effects grasped from the above embodiments and modification examples are described.

[0323] (A) The liquid ejection device includes: a liquid ejection head that ejects liquid from nozzles provided on a nozzle surface; a first storage unit having an introduction unit at an upper portion for introducing the liquid stored in a liquid container, and the liquid level varies within a range lower than the nozzle surface; a second storage unit communicating with the first storage unit via a communication path, and supplying the liquid from the first storage unit to the second storage unit using a head difference; a supply flow path that supplies the liquid from the second storage unit to the liquid ejection head; a pressurizing unit that pressurizes the inside of the second storage unit; and a first valve that can close the communication path when pressurized by the pressurizing unit.

[0324] According to this structure, the communication path communicating with the first storage unit and the supply flow path communicating with the liquid ejection head are connected to the second storage unit. When the pressurizing unit pressurizes the inside of the second storage unit, the communication path can be closed by the first valve. Therefore, the liquid in the pressurized second storage unit is supplied to the liquid ejection head via the supply flow path. Thus, the liquid ejection device can discharge the liquid from the nozzles by pressurizing the liquid inside the liquid ejection head, and the possibility of the liquid ejection head sucking the liquid from the nozzles can be reduced.

[0325] (B) The liquid ejection device may further include: a second valve provided in the supply flow path between the second storage unit and the liquid ejection head, and the second valve can open and close the supply flow path when pressurized by the pressurizing unit.

[0326] According to this structure, when the pressurizing unit pressurizes the inside of the second storage unit with the first valve closing the communication path and the second valve closing the supply flow path, the pressure is accumulated in the second storage unit. Therefore, by opening the second valve while the pressure inside the second storage unit is increasing, a high pressure can be transmitted to the liquid ejection head, and for example, thickened liquid can be easily discharged.

[0327] (C) The liquid ejection device may further include: a recovery flow path that recovers the liquid from the liquid ejection head to the first storage unit; and a third valve that can open and close the recovery flow path.

[0328] According to this structure, when the pressurizing unit pressurizes the inside of the second storage unit with the third valve closing the recovery flow path, the liquid is discharged from the liquid ejection head. When the pressurizing unit pressurizes the inside of the second storage unit with the third valve opening the recovery flow path, the liquid inside the liquid ejection head is recovered to the first storage unit via the recovery flow path. Therefore, for example, maintenance can be selected according to the state of bubbles in the supply flow path and the state of the nozzles, etc.

[0329] (D) The liquid ejection device may also include a micro-pressure applying unit having a liquid chamber partially formed by a flexible member and a pressure applying mechanism capable of applying pressure to the flexible member from the outside of the liquid chamber, and the micro-pressure applying unit is provided in the recovery flow path between the liquid ejection head and the third valve.

[0330] According to this structure, when the pressure applying mechanism applies pressure to the liquid chamber with the third valve closing the recovery flow path, the liquid is discharged from the liquid ejection head. The amount of the liquid discharged at this time is determined by the size of the liquid chamber. Therefore, compared with the case where the second storage unit is pressurized by the pressure applying unit, a micro-pressure capable of precisely applying a degree to break the meniscus formed in the nozzle can be applied to the liquid ejection head.

[0331] (E) In the liquid ejection device, the pressure applying mechanism may also include the pressure applying unit, an air chamber separated from the liquid chamber by the flexible member, and an air flow path connecting the pressure applying unit and the air chamber.

[0332] According to this structure, the pressure applying mechanism includes a pressure applying unit for pressurizing the second storage unit. The pressure applying unit pressurizes the air chamber via the air flow path, thereby pressing the flexible member to pressurize the liquid chamber. Therefore, the liquid in the second storage unit and the liquid in the liquid chamber can be pressurized by the pressure applying unit.

[0333] (F) In the liquid ejection device, the first connection portion of the liquid ejection head and the recovery flow path may also be arranged at a position higher than the second connection portion of the liquid ejection head and the supply flow path.

[0334] According to this structure, the first connection portion to which the recovery flow path is connected is arranged at a position higher than the second connection portion to which the supply flow path is connected. Since the bubbles in the liquid ejection head tend to gather at a higher position due to buoyancy, they are more likely to gather at the first connection portion than at the second connection portion. Therefore, by recovering the liquid in the liquid ejection head to the first storage unit via the recovery flow path, the bubbles can be easily discharged from the liquid ejection head.

[0335] (G) In the liquid ejection device, the first valve may also have a check valve that allows the liquid to flow from the first storage unit to the second storage unit and restricts the liquid from flowing from the second storage unit to the first storage unit.

[0336] For example, when driving the first valve to close the communication path, a driving source for driving the first valve is required. Regarding this point, according to this structure, the first valve has a check valve. Specifically, the first valve allows the liquid supplied from the first storage unit to the second storage unit due to the head difference to flow, and restricts the liquid from flowing from the second storage unit to the first storage unit when the second storage unit is pressurized. Therefore, the first valve does not require driving, and the driving source can be reduced.

[0337] (H) In the liquid ejection device, the liquid ejection head may also be arranged in a posture in which the nozzle surface is inclined with respect to the horizontal.

[0338] According to this structure, the nozzle surface of the liquid ejection head is inclined with respect to the horizontal. Therefore, the degree of freedom in arranging the liquid ejection head can be increased.

[0339] (I) Regarding the control method of the liquid ejection device, the liquid ejection device includes: a liquid ejection head that ejects liquid from a nozzle provided on a nozzle surface; a first storage unit having an introduction unit at an upper part through which the liquid stored in the liquid storage unit can be introduced; a second storage unit communicating with the first storage unit via a communication path; a supply flow path that supplies the liquid from the second storage unit to the liquid ejection head; a first valve that can open and close the communication path; and a pressurizing unit that pressurizes the inside of the second storage unit. In the control method of the liquid ejection device, a pressurized discharge is performed, and the pressurized discharge includes: closing the communication path by the first valve; and pressurizing the inside of the second storage unit by the pressurizing unit to discharge the liquid from the nozzle.

[0340] According to this method, in the pressurized discharge, the communication path is closed by the first valve, and the inside of the second storage unit is pressurized by the pressurizing unit. The liquid in the pressurized second storage unit is supplied to the liquid ejection head via the supply flow path. Therefore, the liquid ejection device can discharge the liquid from the nozzle by pressurizing the liquid inside the liquid ejection head, and the possibility of the liquid ejection head sucking the liquid from the nozzle can be reduced.

[0341] (J) In the control method of the liquid ejection device, it may also be that the liquid ejection device further includes a second valve provided in the supply flow path between the second storage unit and the liquid ejection head and capable of opening and closing the supply flow path. In the control method of the liquid ejection device, a pressure accumulation discharge may also be performed, and the pressure accumulation discharge includes: closing the communication path by the first valve; closing the supply flow path by the second valve; and after pressurizing the inside of the second storage unit by the pressurizing unit, opening the supply flow path by the second valve to discharge the liquid from the nozzle.

[0342] According to this method, in the pressure accumulation discharge, the inside of the second storage unit is pressurized by the pressurizing unit in a state where the first valve closes the communication path and the second valve closes the supply flow path, so that a pressure is accumulated in the second storage unit. In the pressure accumulation discharge, the second valve is opened after pressurizing the inside of the second storage unit, so that the accumulated high pressure can be transmitted to the liquid ejection head, and for example, a thick liquid or the like can be easily discharged.

[0343] (K) In the control method of the liquid ejection device, the following can also be performed: first pressure accumulation discharge, in which when the second storage unit is pressurized at a first pressure, the supply flow path is opened by the second valve; and second pressure accumulation discharge, in which when the second storage unit is pressurized at a second pressure lower than the first pressure, the supply flow path is opened by the second valve.

[0344] In the first pressure accumulation discharge, when the second storage unit is pressurized at the first pressure, the supply flow path is opened by the second valve to discharge the liquid from the nozzle. In the second pressure accumulation discharge, when the second storage unit is pressurized at the second pressure lower than the first pressure, the supply flow path is opened by the second valve to discharge the liquid from the nozzle. Therefore, for example, by combining the first pressure accumulation discharge and the second pressure accumulation discharge according to the structure of the supply flow path, the supply flow path can be efficiently filled with liquid.

[0345] (L) In the control method of the liquid ejection device, the following can also be performed: first pressure accumulation discharge, in which the time for pressurizing the second storage unit by the pressurizing unit is a first time; and second pressure accumulation discharge, in which the time for pressurizing the second storage unit by the pressurizing unit is a second time shorter than the first time.

[0346] Regarding the drive of the pressurizing unit in the state where the communication path and the supply flow path are closed, the longer the drive time, the higher the accumulated pressure. Regarding this point, according to this method, in the first pressure accumulation discharge, after pressurizing the second storage unit for the first time, the supply flow path is opened by the second valve to discharge the liquid from the nozzle. In the second pressure accumulation discharge, after pressurizing the second storage unit for the second time shorter than the first time, the supply flow path is opened by the second valve to discharge the liquid from the nozzle. Therefore, for example, by combining the first pressure accumulation discharge and the second pressure accumulation discharge according to the structure of the supply flow path, the supply flow path can be efficiently filled with liquid.

[0347] (M) In the control method of the liquid ejection device, it may also be that the liquid ejection device further includes: a second valve provided in the supply flow path between the second storage unit and the liquid ejection head, capable of opening and closing the supply flow path; a recovery flow path for recovering the liquid from the liquid ejection head to the first storage unit; and a third valve capable of opening and closing the recovery flow path. In the control method of the liquid ejection device, liquid circulation is performed, and the liquid circulation includes: closing the communication path by the first valve; opening the supply flow path by the second valve; opening the recovery flow path by the third valve; and pressurizing the second storage unit by the pressurizing unit, so that the liquid flows from the second storage unit through the liquid ejection head to the first storage unit.

[0348] According to this method, when liquid circulation is performed, the liquid is recovered from the second storage unit to the first storage unit via the supply flow path, the liquid ejection head, and the recovery flow path. Bubbles in the supply flow path and the liquid ejection head move together with the liquid. Therefore, the bubbles can be recovered without discharging the liquid from the liquid ejection head.

[0349] (N) In the control method of the liquid ejection device, it may also be that the liquid ejection device further includes: a second valve provided in the supply flow path between the second storage unit and the liquid ejection head, capable of opening and closing the supply flow path; a recovery flow path for recovering the liquid from the liquid ejection head to the first storage unit; a third valve capable of opening and closing the recovery flow path; and a micro-pressure unit for pressurizing the liquid in the recovery flow path. The micro-pressure unit is provided in the recovery flow path between the liquid ejection head and the third valve and has a liquid chamber partially formed by a flexible member and a pressurizing mechanism capable of pressurizing the flexible member from the outside of the liquid chamber. In the control method of the liquid ejection device, micro-pressure discharge is performed, and the micro-pressure discharge includes: closing the supply flow path by the second valve; closing the recovery flow path by the third valve; and pressurizing the flexible member by the pressurizing mechanism to discharge the liquid from the nozzle.

[0350] According to this method, in the micro-pressure discharge, with the second valve closing the supply flow path and the third valve closing the recovery flow path, the flexible member is pressurized by the pressurizing mechanism, thereby pressurizing the liquid in the liquid chamber and causing the liquid to be discharged from the liquid ejection head. The amount of the liquid discharged at this time is determined by the size of the liquid chamber. Therefore, compared with the case of pressurizing the inside of the second storage unit by the pressure unit, a micro-pressure that can precisely break the liquid meniscus formed in the nozzle can be applied to the liquid ejection head.

[0351] (O) In the control method of the liquid ejection device, it may also be that the pressurizing mechanism includes the pressure unit, an air chamber separated from the liquid chamber by the flexible member, and an air flow path connecting the pressure unit and the air chamber. In the control method of the liquid ejection device, pressurized air is supplied to the air chamber by the pressure unit, thereby pressurizing the flexible member to perform the micro-pressure discharge.

[0352] According to this method, in the micro-pressure discharge, the pressure unit pressurizes the air chamber via the air flow path and pressurizes the flexible member. Therefore, the liquid in the second storage unit and the liquid in the liquid chamber can be pressurized by the pressure unit.

[0353] (P)In the control method of the liquid ejection device, it may also be that the liquid ejection device further includes: a second valve provided in the supply flow path between the second storage unit and the liquid ejection head, capable of opening and closing the supply flow path; a recovery flow path for recovering the liquid from the liquid ejection head to the first storage unit; and a third valve capable of opening and closing the recovery flow path. In the control method of the liquid ejection device, a head replacement routine is performed, and the head replacement routine includes: closing the communication path by the first valve; opening the supply flow path by the second valve; closing the recovery flow path by the third valve; pressurizing the inside of the second storage unit by the pressurizing unit to discharge the liquid from the second storage unit to the liquid ejection head from the nozzle; opening the recovery flow path by the third valve; and pressurizing the inside of the second storage unit by the pressurizing unit to recover the liquid in the recovery flow path to the first storage unit.

[0354] According to this method, in the head replacement routine, by pressurizing the inside of the second storage unit in a state where the communication path and the recovery flow path are closed and the supply flow path is opened, the liquid in the second storage unit, the supply flow path, and the liquid ejection head is discharged from the nozzle. Then, by pressurizing the inside of the second storage unit in a state where the communication path is closed and the recovery flow path and the supply flow path are opened, the liquid in the recovery flow path is recovered to the first storage unit. Therefore, since the liquid ejection head is replaced in a state where the liquid has been discharged from the supply flow path, the liquid ejection head, and the recovery flow path, it is possible to suppress the dripping of the liquid from the supply flow path, the liquid ejection head, and the recovery flow path.

[0355] (Q)In the control method of the liquid ejection device, it may also be that the liquid ejection head performs printing by ejecting liquid onto a medium. When the ejection flow rate when the liquid ejection head ejects the liquid onto the medium is less than a threshold value, the printing is performed in a state where the supply flow path is opened by the second valve and the recovery flow path is closed by the third valve. When the ejection flow rate when the liquid ejection head ejects the liquid onto the medium is equal to or greater than the threshold value, the printing is performed in a state where the supply flow path is opened by the second valve and the recovery flow path is opened by the third valve.

[0356] According to this method, when the ejection flow rate when ejecting liquid onto the medium is equal to or greater than the threshold value, the supply flow path and the recovery flow path are opened. In addition to supplying liquid from the supply flow path, liquid is also supplied to the liquid ejection head from the recovery flow path, so that the required amount of liquid can be easily supplied.

Claims

1. A liquid ejection device, characterized in that, Comprising: A liquid ejection head that ejects liquid from a nozzle provided on a nozzle surface; A first storage section having an introduction section provided at an upper portion, the introduction section being capable of introducing the liquid stored in a liquid storage section, and the liquid level in the first storage section varying within a range lower than the nozzle surface; A second storage section that is connected to the first storage section via a communication path, and the liquid is supplied from the first storage section to the second storage section by a head difference; A supply flow path that supplies the liquid from the second storage section to the liquid ejection head; A pressurizing section that pressurizes the interior of the second storage section; And A first valve that can close the communication path when pressurized by the pressurizing section.

2. The liquid ejection device according to claim 1, characterized in that, The liquid ejection device further comprises: A second valve that is provided in the supply flow path between the second storage section and the liquid ejection head, and the second valve can open and close the supply flow path when pressurized by the pressurizing section.

3. The liquid ejection device according to claim 1, characterized in that, The liquid ejection device further comprises: 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.

4. The liquid ejection device according to claim 3, characterized in that, The liquid ejection device further comprises: A micro-pressurizing section that has a liquid chamber and a pressurizing mechanism, a part of the liquid chamber being constituted by a flexible member, and the pressurizing mechanism being capable of pressurizing the flexible member from the outside of the liquid chamber, the micro-pressurizing section being provided in the recovery flow path between the liquid ejection head and the third valve.

5. The liquid ejection device according to claim 4, characterized in that, The pressurizing mechanism includes: The pressurizing section; An air chamber that is separated from the liquid chamber by the flexible member; and An air flow path that connects the pressurizing section and the air chamber.

6. The liquid ejection device according to claim 3, characterized in that, The first connection portion between the liquid ejection head and the recovery flow path is arranged at a position higher than the second connection portion between the liquid ejection head and the supply flow path.

7. The liquid ejection device according to any one of claims 1 to 6, characterized in that, The first valve has a check valve that allows the liquid to flow from the first storage section to the second storage section and restricts the liquid from flowing from the second storage section to the first storage section.

8. The liquid ejection device according to any one of claims 1 to 6, characterized in that, The liquid ejection head is arranged in a posture where the nozzle surface is inclined with respect to the horizontal.

9. A control method for a liquid ejection device, characterized in that, The liquid ejection device comprises: A liquid ejection head that ejects liquid from a nozzle provided on a nozzle surface; A first storage section having an introduction section provided at an upper portion, the introduction section being capable of introducing the liquid stored in a liquid storage section; A second storage section that is connected to the first storage section via a communication path; 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 path;And A pressurizing section that pressurizes the interior of the second storage section, In the control method of the liquid ejection device, a pressurized discharge is performed, and the pressurized discharge includes: Closing the communication path by the first valve; And Pressurizing the interior of the second storage section by the pressurizing section to discharge the liquid from the nozzle.

10. The control method of the liquid ejection device according to claim 9, wherein, The liquid ejection device further comprises a second valve that is provided in the supply flow path between the second storage section and the liquid ejection head and can open and close the supply flow path, In the control method of the liquid ejection device, a pressure accumulation discharge is performed, and the pressure accumulation discharge includes: Close the communication path through the first valve; Close the supply flow path through the second valve; and After pressurizing the second storage portion by the pressurizing unit, open the supply flow path through the second valve to discharge the liquid from the nozzle.

11. The control method of the liquid ejection device according to claim 10, wherein, In the control method of the liquid ejecting device, perform: First pressure accumulation discharge, open the supply flow path through the second valve when pressurizing is performed in the second storage portion at a first pressure; And Second pressure accumulation discharge, open the supply flow path through the second valve when pressurizing is performed in the second storage portion at a second pressure lower than the first pressure.

12. The control method of the liquid ejection device according to claim 10, wherein, In the control method of the liquid ejecting device, perform: First pressure accumulation discharge, the time for pressurizing the second storage portion by the pressurizing unit is a first time; And Second pressure accumulation discharge, the time for pressurizing the second storage portion by the pressurizing unit is a second time shorter than the first time.

13. The control method of the liquid ejection device according to claim 9, wherein, The liquid ejecting device further includes: A second valve, provided in the supply flow path between the second storage portion and the liquid ejection head, and capable of opening and closing the supply flow path; A recovery flow path for recovering the liquid from the liquid ejection head to the first storage portion; And A third valve capable of opening and closing the recovery flow path, In the control method of the liquid ejecting device, perform liquid circulation, the liquid circulation includes: Close the communication path through the first valve; Open the supply flow path through the second valve; Open the recovery flow path through the third valve; and Pressurize the second storage portion by the pressurizing unit so that the liquid flows from the second storage portion through the liquid ejection head to the first storage portion.

14. The control method of the liquid ejection device according to claim 9, wherein, The liquid ejecting device further includes: A second valve, provided in the supply flow path between the second storage portion and the liquid ejection head, and capable of opening and closing the supply flow path; A recovery flow path for recovering the liquid from the liquid ejection head to the first storage portion; A third valve capable of opening and closing the recovery flow path; And A micro-pressurizing unit for pressurizing the liquid in the recovery flow path, The micro-pressurizing unit is provided in the recovery flow path between the liquid ejection head and the third valve, and has a liquid chamber and a pressurizing mechanism, a part of the liquid chamber is constituted by a flexible member, and the pressurizing mechanism can pressurize the flexible member from the outside of the liquid chamber; In the control method of the liquid ejecting device, perform micro-pressurization discharge, the micro-pressurization discharge includes: Close the supply flow path through the second valve; Close the recovery flow path through the third valve; and Pressurize the flexible member by the pressurizing mechanism to discharge the liquid from the nozzle.

15. The control method of the liquid ejection device according to claim 14, wherein, The pressurizing mechanism includes: The pressurizing unit; An air chamber separated from the liquid chamber by the flexible member; and An air flow path communicating the pressurizing unit with the air chamber, In the control method of the liquid ejecting device, supply pressurized air to the air chamber by the pressurizing unit, thereby pressurize the flexible member to perform the micro-pressurization discharge.

16. The control method of the liquid ejection device according to claim 9, wherein, The liquid ejecting device further includes: A second valve, disposed in the supply flow path between the second storage unit and the liquid ejection head, and capable of opening and closing the supply flow path; A recovery flow path for recovering the liquid from the liquid ejection head to the first storage unit; And A third valve capable of opening and closing the recovery flow path, In the control method of the liquid ejection device, a head replacement routine is performed, and the head replacement routine includes: Closing the communication path by the first valve; Opening the supply flow path by the second valve; Closing the recovery flow path by the third valve; Pressurizing the inside of the second storage unit by the pressurizing unit, and discharging the liquid from the second storage unit to the liquid ejection head from the nozzle; Opening the recovery flow path by the third valve; and Pressurizing the inside of the second storage unit by the pressurizing unit, and recovering the liquid in the recovery flow path to the first storage unit.

17. The control method of the liquid ejection device according to any one of claims 13 to 16, wherein, The liquid ejection head performs printing by ejecting the liquid onto a medium, When the ejection flow rate when the liquid ejection head ejects the liquid onto the medium is less than a threshold value, the printing is performed in a state where the supply flow path is opened by the second valve and the recovery flow path is closed by the third valve, When the ejection flow rate when the liquid ejection head ejects the liquid onto the medium is equal to or greater than the threshold value, the printing is performed in a state where the supply flow path is opened by the second valve and the recovery flow path is opened by the third valve.

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