JP7567239B2 - Liquid ejection device - Google Patents

Description

The present invention relates to a liquid ejection device such as a printer.

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

JP 2014-024189 A

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

A liquid ejection device that solves the above problem includes a liquid ejection head that ejects liquid from a nozzle provided on a nozzle surface, a first storage section that has an introduction section at its upper portion that can introduce the liquid contained in a liquid storage section and whose liquid level fluctuates within a range lower than the nozzle surface, a second storage section that communicates with the first storage section via a communication passage and to which the liquid is supplied from the first storage section due to a head difference, a supply flow path that supplies the liquid from the second storage section to the liquid ejection head, a pressurizing section that pressurizes the second storage section, and a first valve that can close the communication passage when pressurized by the pressurizing section.

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

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

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

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

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

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

The liquid ejection head 23 may be detachably attached to the main body of the liquid ejection device 11. The liquid ejection head 23 is arranged so that the nozzle surface 21 is inclined relative to the horizontal. The liquid ejection head 23 may perform printing by ejecting liquid onto the medium 12 in an inclined position. The liquid ejection head 23 in this embodiment is a line type that is installed across the width of the medium 12. The liquid ejection head 23 may also be configured as a serial type that performs printing while moving in the width direction of the medium 12.

The supply mechanism 25 may include an attachment portion 28 to which the liquid storage portion 24 is detachably attached. The liquid storage portion 24 may include a storage chamber 29 for storing liquid, an outlet portion 30 for emitting the liquid stored in the storage chamber 29, and a storage portion side valve 31 provided in the outlet portion 30. The storage chamber 29 in this embodiment is an enclosed space that is not connected to the atmosphere. Before being attached to the attachment portion 28, the liquid storage portion 24 may store an amount of liquid greater than the amount of liquid that the supply mechanism 25 can hold.

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

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

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

The drive mechanism 26 includes a pressurizing unit 47 that pressurizes the second storage unit 35. The drive mechanism 26 may include a switching mechanism 48 connected to the pressurizing unit 47 and a pressure sensor 49 that detects pressure. The drive mechanism 26 may include an atmosphere open path 50 connected to the first storage unit 33, a pressurized flow path 51 connected to the second storage unit 35, and a connection flow path 52 that connects the atmosphere open path 50 and the pressurized flow path 51 to the pressurizing unit 47. The drive mechanism 26 may include an air chamber 53 separated from the liquid chamber 41 via a flexible member 42, a spring 54 provided in the air chamber 53, and an air flow path 55 connected to the air chamber 53. The spring 54 reduces pressure fluctuations of the liquid in the recovery flow path 39 and the liquid ejection head 23 by pressing the flexible member 42.

The pressurizing unit 47 is, for example, a tube pump that sends out air by rotating a roller while squashing a tube. One end of a tube (not shown) of the pressurizing unit 47 is connected to an air flow path 55, and the other end is connected to a connection flow path 52. When the pressurizing unit 47 is driven in the forward direction, it sends out air taken in from the air flow path 55 to the connection flow path 52. When the pressurizing unit 47 is driven in the reverse direction, it sends out air taken in from the connection flow path 52 to the air flow path 55.

In this embodiment, the pressurizing mechanism 57 includes the pressurizing unit 47, the air chamber 53, and the air flow path 55 that connects the pressurizing unit 47 and the air chamber 53, and the liquid chamber 41 is added to the pressurizing mechanism 57 to form the micro-pressurizing unit 58. The micro-pressurizing unit 58 has the liquid chamber 41 and the pressurizing mechanism 57 that can pressurize the flexible member 42 from outside the liquid chamber 41. The micro-pressurizing unit 58 is provided in the recovery flow path 39 between the liquid ejection head 23 and the third valve 40, and pressurizes the liquid in the recovery flow path 39.

Next, the first reservoir 33 will be described.
The first reservoir 33 has an introduction portion 60 capable of introducing the liquid contained in the liquid storage portion 24 attached to the attachment portion 28. The first reservoir 33 may have an apparatus-side valve 61 provided in the introduction portion 60, a first reservoir chamber 62 that stores the liquid, a liquid level sensor 63 that detects the amount of liquid stored in the first reservoir chamber 62, and a first gas-liquid separation membrane 64 that separates the first reservoir chamber 62 from the atmospheric open path 50. The first gas-liquid separation membrane 64 is a membrane that has the property of passing gas but not passing liquid.

The storage unit side valve 31 and the device side valve 61 open when the liquid storage unit 24 is attached to the attachment unit 28, and remain open while the liquid storage unit 24 is attached to the attachment unit 28. By configuring the device side valve 61 to open before the storage unit side valve 31 when the liquid storage unit 24 is attached to the attachment unit 28, the risk of liquid leaking from the liquid storage unit 24 can be reduced.

The introduction part 60 is provided at the top of the first storage part 33. In this embodiment, the introduction part 60 is provided by penetrating the ceiling 65 of the first storage chamber 62. The lower end of the introduction part 60 is located inside the first storage chamber 62 and below the ceiling 65. The upper end of the introduction part 60 is located outside the first storage chamber 62 and above the ceiling 65. The introduction part 60 is connected to the outlet part 30 provided in the liquid storage part 24 by mounting the liquid storage part 24 to the mounting part 28.

The lower end of the introduction section 60 is located below the nozzle surface 21. As a result, the first liquid level 66 of the liquid stored in the first storage section 33 fluctuates in a range lower than the nozzle surface 21. Specifically, the liquid in the liquid storage section 24 is supplied to the first storage section 33 through the outlet section 30 and the introduction section 60 by the head. Air is introduced from the first storage section 33 through the introduction section 60 and the outlet section 30 to the liquid storage section 24 by the amount of liquid supplied to the first storage section 33. The first liquid level 66 rises by the amount of liquid supplied. When the first liquid level 66 reaches the lower end of the introduction section 60, the inflow of air from the first storage section 33 to the liquid storage section 24 is restricted. Since the storage chamber 29 is sealed, when the inflow of air is restricted, the pressure in the storage chamber 29 decreases by the amount of liquid supplied. When the negative pressure in the storage chamber 29 becomes greater than the head of the liquid in the storage chamber 29, the supply of liquid from the liquid storage section 24 to the first storage section 33 is restricted.

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

The liquid level sensor 63 may detect that the first liquid level 66 is in a standard position, that the first liquid level 66 is lower than the standard position, or that the first liquid level 66 is in a full position above the standard position. When the first liquid level 66 is in the full position, the first storage section 33 stores the maximum amount of liquid. When the liquid level sensor 63 detects that the first liquid level 66 is lower than the standard position, the control section 19 may determine that the liquid storage section 24 is empty and instruct the user to replace the liquid storage section 24.

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

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

The second storage section 35 is supplied with liquid from the first storage section 33 by the head difference. The first valve 36 may be configured with a check valve that allows the flow of liquid from the first storage section 33 to the second storage section 35 and limits the flow of liquid from the second storage section 35 to the first storage section 33. When the first storage chamber 62 and the second storage chamber 68 are at atmospheric pressure, the second liquid level 70 of the liquid in the second storage section 35 is at the same height as the first liquid level 66. In other words, the second liquid level 70 is maintained at a standard position that is approximately the same height as the lower end of the introduction section 60, and fluctuates in a range lower than the nozzle surface 21. The liquid in the liquid ejection head 23 is maintained at a negative pressure by the head difference with the liquid in the first storage section 33 and the second storage section 35. When the liquid is consumed in the liquid ejection head 23, the liquid stored in the second storage section 35 is supplied to the liquid ejection head 23.

The first valve 36 closes the communication passage 34 when the pressure in the second storage section 35 is greater than the pressure in the first storage section 33. Therefore, the first valve 36 closes the communication passage 34 when the pressure in the second storage section 35 is increased by the pressurizing section 47.

The second valve 38 and the third valve 40 are controlled to open and close by the control unit 19. The second valve 38 is provided so as to be able to open and close the supply flow path 37 when pressurized by the pressurizing unit 47. The third valve 40 is provided so as to be able to open and close the recovery flow path 39.

Next, the switching mechanism 48 will be described.
The switching mechanism 48 includes a thin tube section 72 provided in the connection flow path 52, and a first selection valve 73a to an eleventh selection valve 73k that can open and close the flow path. The thin tube section 72 is a meandering tube that is thin enough that the flow of liquid is significantly restricted relative to the flow of air.

The first selection valve 73a opens to connect the air flow path 55 to the atmosphere. The second selection valve 73b opens to connect the air flow path 55 to the pressure sensor 49. The third selection valve 73c opens to open the air flow path 55 and connects the pressurizing section 47 to the air chamber 53.

The fourth selection valve 73d opens the connection flow path 52 between the pressurizing section 47 and the eighth selection valve 73h to the atmosphere. The fifth selection valve 73e opens the connection flow path 52 to the pressure sensor 49. The sixth selection valve 73f and the seventh selection valve 73g open the connection flow path 52 to the atmosphere. The eighth selection valve 73h opens the connection flow path 52. The ninth selection valve 73i opens the thin tube section 72 to the atmosphere. The tenth selection valve 73j opens the atmosphere release path 50 to connect the first storage section 33 to the connection flow path 52. The eleventh selection valve 73k opens the pressurizing flow path 51 to connect the second storage section 35 to the connection flow path 52.

When the pressure in the air chamber 53 is changed, 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 unit 47 is driven in the forward direction in this state, the air in the air chamber 53 is discharged through the air flow path 55 and the connecting flow path 52, and the pressure in the air chamber 53 decreases. When the pressurizing unit 47 is driven in the reverse direction in this state, air is sent into the air chamber 53 through the connecting flow path 52 and the air flow path 55, and the pressure in the air chamber 53 increases. At this time, the pressure sensor 49 may detect the pressure in the air flow path 55 and the air chamber 53. The control unit 19 may control the drive of the pressurizing unit 47 based on the detection result of the pressure sensor 49.

When the first storage section 33 is opened to the atmosphere, the switching mechanism 48 opens the sixth selection valve 73f and the tenth selection valve 73j. The first storage chamber 62 is connected to the atmosphere via the atmosphere open path 50 and the connection flow path 52.

When the second storage section 35 is opened to the atmosphere, the switching mechanism 48 opens the seventh selection valve 73g and the eleventh selection valve 73k. The second storage chamber 68 is connected to the atmosphere via the pressurized flow path 51 and the connecting flow path 52.

When pressurizing the second storage section 35, the switching mechanism 48 opens the first selection valve 73a, the fifth selection valve 73e, the eighth selection valve 73h, and the eleventh selection valve 73k, and closes the other selection valves. When the pressurizing section 47 rotates forward in this state, air flows into the second storage chamber 68 via 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 may detect the pressure in the connection flow path 52, the pressurizing flow path 51, and the second storage chamber 68. The control section 19 may control the operation of the pressurizing section 47 based on the detection result of the pressure sensor 49.

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

The liquid filling routine shown in FIG. 3 may be executed when the liquid storage unit 24 is first attached to the mounting unit 28. The liquid filling routine may be executed when the liquid storage unit 24 is attached to the mounting unit 28 after the liquid ejection head 23 has been replaced. In the initial state, the second valve 38, the third valve 40, and all the selection valves of the switching mechanism 48 are closed.

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 located at the standard position. If the first liquid level 66 is not located at the standard position, step S103 becomes NO, and the control unit 19 waits until the first liquid level 66 is located at the standard position. If the first liquid level 66 is located at the standard position, step S103 becomes YES, and the control unit 19 transitions to step S104.

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.

In step S107, the control unit 19 determines whether the first liquid level 66 is located at the full position. If the first liquid level 66 is not located at the full position, step S107 becomes NO, and the control unit 19 waits until the first liquid level 66 is located at the full position. If the first liquid level 66 is located at the full position, step S107 becomes YES, and the control unit 19 transitions to step S108.

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 passage 37 to the nozzle 22. If the filling time has not elapsed, step S109 becomes NO, and the control unit 19 waits until the filling time has elapsed. When the filling time has elapsed, step S109 becomes YES, and the control unit 19 transitions the process to step S110. In step S110, the control unit 19 stops driving 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.

Here, steps S104 and S105 may be performed simultaneously with step S106 or after step S106. Also, step S110 may be performed simultaneously with step S111 or after step S111.

Next, the operation when filling with liquid will be described.
2, when the liquid storage portion 24 is attached to the attachment portion 28 and the first storage portion 33 is opened to the atmosphere, liquid is supplied from the liquid storage portion 24 to the first storage portion 33. At this time, since the second storage portion 35 is also open to the atmosphere, the liquid supplied to the first storage portion 33 also flows into the second storage portion 35. The first liquid level 66 and the second liquid level 70 rise to their standard positions.

When the liquid level sensor 63 detects that the first liquid level 66 is at the standard position, 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 closes the communication passage 34. 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.

When the liquid level sensor 63 detects that the first liquid level 66 is at the full position, the control unit 19 closes the third valve 40. This stops the inflow of liquid into the first storage unit 33. The liquid in the second storage unit 35 fills the liquid ejection head 23 and is discharged from the nozzle 22.

When the liquid ejection head 23 is filled with liquid, the control unit 19 opens the second storage unit 35 to the atmosphere. This opens the first valve 36 and opens the communication passage 34. The liquid in the first storage unit 33 is supplied to the second storage unit 35 via the communication passage 34. The control unit 19 may close the second valve 38.

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

In step S201, the control unit 19 opens the second valve 38. In step S202, the control unit 19 opens the third valve 40. In step S203, the control unit 19 opens the first storage unit 33 to the atmosphere. In step S204, the control unit 19 pressurizes the second storage unit 35.

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

Here, steps S201 and S202 may be performed simultaneously with step S203 or after step S203, and may be performed simultaneously with step S204 or after step S204. Also, step S206 may be performed simultaneously with step S207 or after step S207.

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

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

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

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

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

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

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

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

The pressurization and discharge routine shown in FIG. 6 is executed when an instruction to execute pressurization and discharge is issued, or when a discharge failure occurs in which liquid cannot be normally discharged from the nozzles 22, or the like.
In step S401, the control unit 19 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 second storage unit 35. In step S404, the control unit 19 determines whether or not a pressurization discharge time has elapsed since the second storage unit 35 was pressurized. The pressurization discharge time is the time required for the pressure pressurizing the second storage unit 35 to be transmitted to the nozzle 22 via the supply flow path 37, and for the liquid to be discharged from the nozzle 22 to restore the state of the nozzle 22.

Until the pressurization and discharge time has elapsed, step S404 remains NO, and the control unit 19 waits until the pressurization and discharge time has elapsed. When the pressurization and discharge time has elapsed, step S404 remains YES, and the control unit 19 transitions 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 and discharge routine.

Here, steps S401 and S402 may be performed simultaneously with step S403 or after step S403. Also, step S405 may be performed simultaneously with step S406 or after step S406.

Next, the operation when pressure discharge is performed will be described.
2, the liquid ejection device 11 pressurizes the second storage section 35 using the pressurizing section 47 to eject the liquid from the nozzle 22. At this time, the pressure in the second storage section 35 becomes higher than the pressure in the first storage section 33, so that the first valve 36 closes. That is, by pressurizing the second storage section 35, the liquid ejection device 11 closes the communication passage 34 using the first valve 36.

When the pressurization and discharge time has elapsed since pressurizing the second storage section 35, the control section 19 closes the second valve 38. This stops the discharge of liquid from the nozzle 22. When the second storage section 35 is opened to the atmosphere, the first valve 36 opens and liquid is supplied from the first storage section 33 to the second storage section 35.

The accumulated pressure discharge routine shown in FIG. 7 may be executed when execution of accumulated pressure discharge is instructed, or when the discharge defect is not improved even after execution of pressurized discharge.
In step S501, the control unit 19 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 the execution of the first accumulated pressure discharge has been instructed, or whether the execution of the second accumulated pressure discharge, which accumulates a smaller pressure than the first accumulated pressure discharge, has been instructed. If the first accumulated pressure discharge is to be executed, step S503 becomes YES, and the control unit 19 transitions the process to step S504. In step S504, the control unit 19 sets the accumulated pressure time to the first time.

If the second accumulated pressure discharge is to be performed in step S503, step S503 becomes NO, and the control unit 19 transitions the process to step S505. In step S505, the control unit 19 sets the accumulated pressure time to a second time that is shorter than the first time.

In step S506, the control unit 19 pressurizes the second storage unit 35. In step S507, the control unit 19 determines whether or not the pressure accumulation time has elapsed since the start of pressurization in the second storage unit 35. If the pressure accumulation time has not elapsed, step S507 becomes NO, and the control unit 19 waits until the pressure accumulation time has elapsed. If the pressure accumulation time has elapsed, step S507 becomes YES, and the control unit 19 transitions to step S508.

In step S508, the control unit 19 opens the second valve 38. In step S509, the control unit 19 determines whether or not the accumulated pressure discharge time has elapsed since the second valve 38 was opened. The accumulated pressure discharge time is the time required for the pressure accumulated in the second storage unit 35 to be transmitted to the nozzle 22 via the supply flow path 37 and for the liquid to be discharged from the nozzle 22.

Until the accumulated pressure discharge time has elapsed, step S509 becomes NO, and the control unit 19 waits until the accumulated pressure discharge time has elapsed. When the accumulated pressure discharge time has elapsed, step S509 becomes YES, and the control unit 19 transitions 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 accumulated pressure discharge routine.

Here, steps S501 and S502 may be performed simultaneously with the start of pressurization in step S506, or immediately after the start of pressurization in step S506. Also, step S510 may be performed simultaneously with step S511, or after step S511. Also, step S510 does not have to be performed.

Next, the operation when discharging the accumulated pressure will be described.
2, the control unit 19 closes the second valve 38, and the second valve 38 closes the supply flow path 37. The liquid ejection device 11 pressurizes the inside of the second storage unit 35 by the pressurizing unit 47. At this time, the pressure in the second storage unit 35 becomes higher than the pressure in the first storage unit 33, and therefore the first valve 36 closes. That is, by pressurizing the second storage unit 35, the liquid ejection device 11 closes the communication passage 34 by the first valve 36.

The liquid ejection device 11 pressurizes the second storage section 35 by the pressurizing section 47, and then opens the supply flow path 37 by the second valve 38 to discharge the liquid from the nozzle 22. The magnitude of the pressure stored in the second storage section 35 is proportional to the time for which the second storage section 35 is pressurized with the communication passage 34 and the supply flow path 37 blocked. In the first accumulated pressure discharge, the time for which the second storage section 35 is pressurized by the pressurizing section 47 is a first time. In the second accumulated pressure discharge, the time for which the second storage section 35 is pressurized by the pressurizing section 47 is a second time that is shorter than the first time. The pressure stored in the first accumulated pressure discharge is greater than the pressure stored in the second accumulated pressure discharge. In other words, in the first accumulated pressure discharge, the supply flow path 37 is opened by the second valve 38 when the second storage section 35 is pressurized with the first pressure. The second accumulated pressure discharge opens the supply flow path 37 by the second valve 38 when the second storage section 35 is pressurized at a second pressure lower than the first pressure.

When the accumulated pressure discharge time has elapsed since pressurizing the second storage section 35, the control section 19 closes the second valve 38. This stops the discharge of liquid from the nozzle 22. When the second storage section 35 is opened to the atmosphere, the first valve 36 opens and liquid is supplied from the first storage section 33 to the second storage section 35.

The slight pressure discharge routine shown in FIG. 8 may be executed when a command to execute slight pressure discharge is issued.
In step S601, the control unit 19 opens the second valve 38. In step S602, the control unit 19 opens the third valve 40. In step S603, the control unit 19 depressurizes the air chamber 53. In step S604, the control unit 19 determines whether or not a depressurization time has elapsed since the air chamber 53 was depressurized. The depressurization time is the time required to deform the flexible member 42 and maximize the volume of the liquid chamber 41.

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

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

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

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

Next, the operation when slight pressure discharge is performed will be described.
2, the control unit 19 opens the second valve 38 and the third valve 40 to open the supply flow path 37 and the recovery flow path 39. The control unit 19 reduces the pressure in the air chamber 53 and deforms the flexible member 42 to increase the volume of the liquid chamber 41. Liquid flows into the liquid chamber 41 from the first storage unit 33 via the recovery flow path 39, and liquid also flows into the liquid chamber 41 from the second storage unit 35 via the supply flow path 37 and the recovery flow path 39.

When the volume of the liquid chamber 41 reaches its maximum, the control unit 19 closes the second valve 38, which closes the supply flow path 37. The control unit 19 closes the third valve 40, which closes the recovery flow path 39. In this state, the liquid ejection device 11 pressurizes the flexible member 42 by sending pressurized air to the air chamber 53 with the pressurizing unit 47. That is, the liquid ejection device 11 pressurizes the flexible member 42 with 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 meniscus formed in the nozzle 22. The amount of liquid ejected from the liquid ejection head 23 by the slight pressurized ejection is less than the amount of liquid ejected from the liquid ejection head 23 by the pressurized ejection.

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

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

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

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

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

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

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

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

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

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

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

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

(3) When the pressurizing unit 47 pressurizes the second storage section 35 while the third valve 40 closes the recovery flow path 39, the liquid is discharged from the liquid ejection head 23. When the pressurizing unit 47 pressurizes the second storage section 35 while the third valve 40 opens the recovery flow path 39, the liquid in the liquid ejection head 23 passes through the recovery flow path 39 and is recovered into the first storage section 33. Therefore, maintenance can be selected according to, for example, the state of the air bubbles in the supply flow path 37 and the state of the nozzle 22.

(4) When the pressurizing mechanism 57 pressurizes the liquid chamber 41 while the third valve 40 closes the recovery flow path 39, liquid is discharged from the liquid ejection head 23. The amount of liquid discharged at this time is determined by the size of the liquid chamber 41. Therefore, compared to when the pressurizing unit 47 pressurizes the second storage unit 35, it is possible to precisely apply a slight pressure to the liquid ejection head 23 that is enough to break the meniscus formed in the nozzle 22.

(5) The pressurizing mechanism 57 includes a pressurizing unit 47 that pressurizes the second storage unit 35. The pressurizing unit 47 pressurizes the air chamber 53 via the air flow path 55, thereby pushing the flexible member 42 and pressurizing the liquid chamber 41. Therefore, the pressurizing unit 47 can pressurize the liquid in the second storage unit 35 and the liquid in the liquid chamber 41.

(6) The first connection part 44 to which the recovery flow path 39 is connected is positioned higher than the second connection part 45 to which the supply flow path 37 is connected. Air bubbles in the liquid ejection head 23 tend to gather at higher positions due to buoyancy, and therefore tend to gather at the first connection part 44 rather than 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, air bubbles can be easily discharged from the liquid ejection head 23.

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

(8) The nozzle surface 21 of the liquid ejection head 23 is inclined relative to the horizontal. This improves the degree of freedom in the arrangement of the liquid ejection head 23.
(9) In the pressurized discharge, the communication passage 34 is closed by the first valve 36, and the inside of the second storage section 35 is pressurized by the pressurizing section 47. The pressurized liquid in the second storage section 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 risk of the liquid ejection head 23 drawing in the liquid from the nozzle 22 can be reduced.

(10) In the discharge of accumulated pressure, the first valve 36 closes the communication passage 34, and the second valve 38 closes the supply flow path 37, and the pressurizing unit 47 pressurizes the second storage unit 35, thereby storing pressure in the second storage unit 35. In the discharge of accumulated pressure, the second valve 38 is opened after pressurizing the second storage unit 35, so that the high accumulated pressure can be transmitted to the liquid ejection head 23, making it easier to discharge, for example, a viscous liquid.

(11) In the first accumulated pressure discharge, when the second storage section 35 is pressurized with a first pressure, the second valve 38 opens the supply flow path 37 to discharge liquid from the nozzle 22. In the second accumulated pressure discharge, when the second storage section 35 is pressurized with a second pressure lower than the first pressure, the second valve 38 opens the supply flow path 37 to discharge liquid from the nozzle 22. Therefore, for example, by combining the first accumulated pressure discharge and the second accumulated pressure discharge in accordance with the configuration of the supply flow path 37, the supply flow path 37 can be efficiently filled with liquid.

(12) When the pressurizing unit 47 is driven with the communication passage 34 and the supply flow path 37 closed, the longer the drive time, the higher the accumulated pressure becomes. In this regard, the first accumulated pressure discharge pressurizes the second storage unit 35 for a first time, and then the second valve 38 opens the supply flow path 37 to discharge the liquid from the nozzle 22. The second accumulated pressure discharge pressurizes the second storage unit 35 for a second time that is shorter than the first time, and then the second valve 38 opens the supply flow path 37 to discharge the liquid from the nozzle 22. Therefore, for example, by combining the first accumulated pressure discharge and the second accumulated pressure discharge in accordance with the configuration of the supply flow path 37, the supply flow path 37 can be filled efficiently.

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

(14) In the case of slight pressure discharge, the second valve 38 closes the supply flow path 37 and the third valve 40 closes the recovery flow path 39, and the flexible member 42 is pressurized by the pressurizing mechanism 57 to pressurize the liquid in the liquid chamber 41 and discharge the liquid from the liquid discharge head 23. The amount of liquid discharged at this time is determined by the size of the liquid chamber 41. Therefore, compared to when the pressurizing unit 47 pressurizes the second storage unit 35, a slight pressure sufficient to break the meniscus formed in the nozzle 22 can be applied to the liquid discharge head 23 with high accuracy.

(15) In the case of slight pressure discharge, the pressurizing unit 47 pressurizes the air chamber 53 through the air flow path 55, thereby pressurizing the flexible member 42. Therefore, the pressurizing unit 47 can pressurize the liquid in the second storage unit 35 and the liquid in the liquid chamber 41.

(16) The head replacement routine closes the communication passage 34 and the recovery flow passage 39, and pressurizes the second storage section 35 with the supply flow passage 37 open, thereby discharging the liquid in the second storage section 35, the supply flow passage 37, and the liquid ejection head 23 from the nozzle 22. Then, the communication passage 34 is closed, and the second storage section 35 is pressurized with the recovery flow passage 39 and the supply flow passage 37 open, thereby recovering the liquid in the recovery flow passage 39 to the first storage section 33. Therefore, the replacement of the liquid ejection head 23 is performed with the liquid discharged from the supply flow passage 37, the liquid ejection head 23, and the recovery flow passage 39, so that dripping of the liquid from the supply flow passage 37, the liquid ejection head 23, and the recovery flow passage 39 can be suppressed.

(17) If the discharge flow rate when discharging liquid onto the medium 12 is equal to or greater than a threshold value, the supply flow path 37 and the recovery flow path 39 are opened. Since liquid is supplied to the liquid discharge head 23 from the recovery flow path 39 in addition to the supply flow path 37, the required amount of liquid can be easily supplied.

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

The control unit 19 may control the opening and closing of the first valve 36. The control unit 19 may close the communication passage 34 by the first valve 36 before the inside of the second storage unit 35 is pressurized.
The second accumulated pressure may be discharged by pressurizing second storage section 35 for a first time with first valve 36 and second valve 38 closed to bring the pressure in second storage section 35 to a first pressure, and then opening first valve 36 to reduce the pressure in second storage section 35 to the second pressure, and then opening second valve 38.

- For slight pressure discharge, the liquid in the liquid chamber 41 may be pressurized by the spring 54 pressing the flexible member 42. In this case, the control unit 19 reduces the pressure in the air chamber 53 to increase the volume of the liquid chamber 41, and then opens the air chamber 53 to the atmosphere. When the air chamber 53 reaches atmospheric pressure, the spring 54 presses the liquid in the liquid chamber 41, causing the liquid to be discharged from the liquid ejection head 23. In the case of a configuration in which the spring 54 presses the flexible member 42, the spring 54 is included in the pressure mechanism 57.

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

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

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

- The liquid level sensor 63 may detect that the first liquid level 66 is located at an end position that is lower than the standard position. When the liquid level sensor 63 detects that the first liquid level 66 is located at the end position, the control unit 19 may notify that the first storage section 33 is empty. The end position is such that printing on one medium 12 can be completed if the total amount of liquid stored in the first storage section 33 and the second storage section 35 when the first liquid level 66 and the second liquid level 70 are located at the end positions is greater than the amount of liquid required to print on one medium 12.

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

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

- The control unit 19 may reduce the pressure inside the first storage unit 33 when liquid is flowed from the recovery flow path 39 into the first storage unit 33. For example, the atmosphere open path 50 may be connected to the air flow path 55. By driving the pressurizing unit 47 in the forward direction, the second storage unit 35 may be pressurized and the first storage unit 33 may be reduced in pressure via the air flow path 55 and the atmosphere open path 50.

The control unit 19 may remove air bubbles from the liquid by reducing the pressure inside the first storage unit 33 and expanding the air bubbles contained in the liquid stored in the first storage unit 33.
Liquid filling, pressurized discharge, slightly pressurized discharge, and liquid circulation may be performed multiple times or in combination. If the amount of liquid that can be stored in the first storage section 33 is less than the amount of liquid filled in the supply flow path 37, the recovery flow path 39, and the liquid ejection head 23, liquid may be filled into the supply flow path 37, the recovery flow path 39, and the liquid ejection head 23 by performing liquid filling multiple times. For example, slightly pressurized discharge may be performed after liquid filling. By combining liquid filling and slightly pressurized discharge, the occurrence of ejection defects can be reduced compared to when only liquid filling is performed.

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

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

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

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

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

The technical ideas and effects obtained from the above-described embodiment and modified examples will be described below.
(A) A liquid ejection device includes a liquid ejection head which ejects liquid from a nozzle provided on a nozzle surface, a first storage section having an introduction section at an upper portion into which the liquid contained in a liquid storage section can be introduced and in which the liquid level fluctuates within a range lower than the nozzle surface, a second storage section which is connected to the first storage section via a communication passage and to which the liquid is supplied from the first storage section due to a head difference, a supply flow path which supplies the liquid from the second storage section to the liquid ejection head, a pressurizing section which pressurizes the second storage section, and a first valve which can close the communication passage when pressurized by the pressurizing section.

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

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

With this configuration, when the first valve closes the communication passage and the second valve closes the supply flow path, the pressurizing unit pressurizes the second storage unit, and pressure is stored in the second storage unit. Therefore, by opening the second valve when the pressure in the second storage unit is high, high pressure can be transmitted to the liquid ejection head, making it easier to eject, for example, thickened liquid.

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

(D) The liquid ejection device may have a liquid chamber, a portion of which is made of a flexible member, and a pressurizing mechanism capable of pressurizing the flexible member from outside the liquid chamber, and may further include a micro-pressurizing unit provided in the recovery flow path between the liquid ejection head and the third valve.

With this configuration, when the pressurizing mechanism pressurizes the liquid chamber while the third valve closes the recovery flow path, liquid is discharged from the liquid ejection head. The amount of liquid discharged at this time is determined by the size of the liquid chamber. Therefore, compared to when the pressurizing unit pressurizes the second storage section, it is possible to precisely apply a slight pressure to the liquid ejection head that is enough to break the meniscus formed in the nozzle.

(E) In the liquid ejection device, the pressurizing mechanism may include the pressurizing unit, an air chamber separated from the liquid chamber via the flexible member, and an air flow path connecting the pressurizing unit and the air chamber.

According to this configuration, the pressurizing mechanism includes a pressurizing unit that pressurizes the second storage unit. The pressurizing unit pressurizes the air chamber through the air flow path, thereby pushing the flexible member and pressurizing the liquid chamber. Therefore, the pressurizing unit can pressurize the liquid in the second storage unit and the liquid in the liquid chamber.

(F) In the liquid ejection device, a first connection portion between the liquid ejection head and the recovery passage may be disposed at a higher position than a second connection portion between the liquid ejection head and the supply passage.
According to this configuration, the first connection part to which the recovery flow path is connected is disposed at a higher position than the second connection part to which the supply flow path is connected. Bubbles in the liquid ejection head tend to gather at higher positions due to buoyancy, and therefore tend to gather at the first connection part rather than the second connection part. Therefore, by recovering the liquid in the liquid ejection head to the first storage part via the recovery flow path, it is possible to easily expel bubbles from the liquid ejection head.

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

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

(H) In the liquid ejection device, the liquid ejection head may be disposed so that the nozzle surface is inclined relative to the horizontal.
According to this configuration, the nozzle surface of the liquid ejection head is inclined relative to the horizontal, which improves the degree of freedom in the arrangement of the liquid ejection head.

(I) A method for controlling a liquid ejection device that includes a liquid ejection head that ejects liquid from a nozzle provided on a nozzle surface, a first storage section having an introduction section provided at the top that can introduce the liquid contained in a liquid storage section, a second storage section that communicates with the first storage section via a communication passage, a supply flow path that supplies the liquid from the second storage section to the liquid ejection head, a first valve that can open and close the communication passage, and a pressurizing section that pressurizes the second storage section, and performs pressurization and discharge including closing the communication passage with the first valve and pressurizing the second storage section with the pressurizing section to discharge the liquid from the nozzle.

According to this method, the pressurized discharge is performed by closing the communication passage with the first valve and pressurizing the second storage section with the pressurizing section. The pressurized liquid in the second storage section 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 in the liquid ejection head, reducing the risk of the liquid ejection head drawing in the liquid from the nozzle.

(J) In the method for controlling a liquid ejection device, the liquid ejection device may further include a second valve provided in the supply flow path between the second storage section and the liquid ejection head and capable of opening and closing the supply flow path, and may perform pressure accumulation and discharge including closing the communication passage with the first valve, closing the supply flow path with the second valve, and pressurizing the second storage section with the pressurizing section, and then opening the supply flow path with the second valve to discharge the liquid from the nozzle.

According to this method, the accumulated pressure discharge is performed by pressurizing the second storage section with the pressurizing unit while the first valve closes the communication passage and the second valve closes the supply flow path, thereby storing pressurized pressure in the second storage section. Since the accumulated pressure discharge is performed by opening the second valve after pressurizing the second storage section, the accumulated high pressure can be transmitted to the liquid ejection head, making it easier to discharge, for example, thickened liquid.

(K) The control method for the liquid ejection device may include a first accumulated pressure discharge in which the second valve opens the supply flow path when the second storage section is pressurized with a first pressure, and a second accumulated pressure discharge in which the second valve opens the supply flow path when the second storage section is pressurized with a second pressure lower than the first pressure.

The first accumulated pressure discharge opens the supply flow path with the second valve when the second storage section is pressurized with a first pressure, and discharges liquid from the nozzle. The second accumulated pressure discharge opens the supply flow path with the second valve when the second storage section is pressurized with a second pressure lower than the first pressure, and discharges liquid from the nozzle. Therefore, for example, by combining the first accumulated pressure discharge and the second accumulated pressure discharge in accordance with the configuration of the supply flow path, the supply flow path can be filled with liquid efficiently.

(L) The control method for the liquid ejection device may include a first accumulated pressure discharge in which the pressurizing unit applies pressure to the second storage unit for a first time, and a second accumulated pressure discharge in which the pressurizing unit applies pressure to the second storage unit for a second time that is shorter than the first time.

When the pressurizing unit is driven with the communication passage and the supply flow path closed, the longer the drive time, the higher the accumulated pressure becomes. In this regard, according to this method, the first accumulated pressure discharge pressurizes the second storage unit for a first time, and then the second valve opens the supply flow path to discharge the liquid from the nozzle. The second accumulated pressure discharge pressurizes the second storage unit for a second time that is shorter than the first time, and then the second valve opens the supply flow path to discharge the liquid from the nozzle. Therefore, for example, by combining the first accumulated pressure discharge and the second accumulated pressure discharge in accordance with the configuration of the supply flow path, the supply flow path can be filled efficiently with liquid.

(M) In a method for controlling a liquid ejection device, the liquid ejection device may further include a second valve provided in the supply flow path between the second storage section and the liquid ejection head and capable of opening and closing the supply flow path, a recovery flow path that recovers the liquid from the liquid ejection head to the first storage section, and a third valve that can open and close the recovery flow path, and may perform liquid circulation including closing the communication passage with the first valve, opening the supply flow path with the second valve, opening the recovery flow path with the third valve, and pressurizing the second storage section with the pressurizing section to cause the liquid to flow from the second storage section to the first storage section via the liquid ejection head.

According to this method, when liquid circulation is performed, the liquid is collected in the first storage section from the second storage section via the supply flow path, the liquid ejection head, and the recovery flow path. The air bubbles in the supply flow path and the liquid ejection head move together with the liquid. Therefore, the air bubbles can be collected without discharging the liquid from the liquid ejection head.

(N) In a method for controlling a liquid ejection device, the liquid ejection device further includes a second valve provided in the supply flow path between the second storage section and the liquid ejection head and capable of opening and closing the supply flow path, a recovery flow path that recovers the liquid from the liquid ejection head to the first storage section, a third valve capable of opening and closing the recovery flow path, and a micro-pressurizing unit that pressurizes the liquid in the recovery flow path, and 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, a part of which is made of a flexible member, and a pressurizing mechanism that can pressurize the flexible member from outside the liquid chamber, and may perform micro-pressurizing and discharging including closing the supply flow path with the second valve, closing the recovery flow path with the third valve, and pressurizing the flexible member with the pressurizing mechanism to discharge the liquid from the nozzle.

According to this method, slight pressure discharge is achieved by pressurizing the flexible member with the pressurizing mechanism while the second valve closes the supply flow path and the third valve closes the recovery flow path, thereby pressurizing the liquid in the liquid chamber and discharging the liquid from the liquid ejection head. The amount of liquid discharged at this time is determined by the size of the liquid chamber. Therefore, compared to when the pressurizing unit pressurizes the second storage section, a slight pressure sufficient to break the meniscus formed in the nozzle can be applied to the liquid ejection head with high accuracy.

(O) In the method for controlling a liquid ejection device, the pressurizing mechanism may include the pressurizing unit, an air chamber separated from the liquid chamber via the flexible member, and an air flow path connecting the pressurizing unit and the air chamber, and the pressurizing unit may send pressurized air to the air chamber to pressurize the flexible member and perform the slight pressurization discharge.

According to this method, the slight pressure discharge is performed by the pressurizing unit pressurizing the air chamber through the air flow path and pressurizing the flexible member. Therefore, the pressurizing unit can pressurize the liquid in the second storage section and the liquid in the liquid chamber.

(P) In the method for controlling a liquid ejection device, the liquid ejection device may further include a second valve provided in the supply flow path between the second storage section and the liquid ejection head and capable of opening and closing the supply flow path, a recovery flow path that recovers the liquid from the liquid ejection head to the first storage section, and a third valve that can open and close the recovery flow path, and may perform a head replacement routine that includes closing the communication path with the first valve, opening the supply flow path with the second valve, closing the recovery flow path with the third valve, pressurizing the second storage section with the pressurizing section to discharge the liquid from the second storage section to the liquid ejection head from the nozzle, opening the recovery flow path with the third valve, and pressurizing the second storage section with the pressurizing section to recover the liquid in the recovery flow path to the first storage section.

According to this method, the head replacement routine closes the communication passage and the recovery passage, and pressurizes the second storage section with the supply passage open, thereby discharging the liquid in the second storage section, the supply passage, and the liquid ejection head from the nozzle. Then, the communication passage is closed, and pressurizes the second storage section with the recovery passage and the supply passage open, thereby recovering the liquid in the recovery passage into the first storage section. Therefore, the replacement of the liquid ejection head is performed with the liquid discharged from the supply passage, the liquid ejection head, and the recovery passage, so that dripping of liquid from the supply passage, the liquid ejection head, and the recovery passage can be suppressed.

(Q) In a method for controlling a liquid ejection device, the liquid ejection head performs printing by ejecting liquid onto a medium, and if 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 with the supply flow path opened by the second valve and the recovery flow path closed by the third valve, and if 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 with the supply flow path opened by the second valve and the recovery flow path opened by the third valve.

According to this method, if the discharge flow rate when discharging liquid onto a medium is equal to or greater than a threshold value, the supply flow path and the recovery flow path are opened. Since liquid is supplied to the liquid discharge head from the recovery flow path in addition to the supply flow path, the required amount of liquid can be easily supplied.

11...Liquid ejection device, 12...Medium, 13...Medium storage section, 14...Stacker, 15...Operation section, 16...Image reading section, 17...Automatic feed section, 19...Control section, 21...Nozzle surface, 22...Nozzle, 23...Liquid ejection head, 24...Liquid storage section, 25...Supply mechanism, 26...Drive mechanism, 28...Mounting section, 29...Storage chamber, 30...Outlet section, 31...Storage section side valve, 33...First storage section, 34...Communication passage, 35...Second storage section, 36...First valve, 37...Supply flow path, 38...Second valve, 39...Recovery flow path, 40...Third valve, 41...Liquid chamber, 42...Flexible member, 44...First connection section, 45...Second connection section, 47...Pressure section, 48...Switching mechanism, 49...Pressure sensor , 50...atmospheric open path, 51...pressurized flow path, 52...connection flow path, 53...air chamber, 54...spring, 55...air flow path, 57...pressurizing mechanism, 58...micro-pressurizing section, 60...introduction section, 61...device side valve, 62...first storage chamber, 63...liquid level sensor, 64...first gas-liquid separation membrane, 65...ceiling, 66...first liquid level, 68...second storage chamber, 69...second gas-liquid separation membrane, 70...second liquid level, 72...thin tube section, 73a...first selection valve, 73b...second selection valve, 73c...third selection valve, 73d...fourth selection valve, 73e...fifth selection valve, 73f...sixth selection valve, 73g...seventh selection valve, 73h...eighth selection valve, 73i...ninth selection valve, 73j...tenth selection valve, 73k...eleventh selection valve.

Claims (22)

a liquid ejection head that ejects liquid from nozzles provided on a nozzle surface;
a first reservoir having an inlet provided at an upper portion thereof and connected to an outlet of a liquid storage portion that stores liquid , the inlet being capable of introducing the liquid, and the liquid level fluctuating within a range lower than the nozzle surface;
a second storage portion that communicates with the first storage portion via a communication passage and to which the liquid is supplied from the first storage portion due to a head difference;
a supply flow path that supplies the liquid from the second reservoir to the liquid ejection head;
a recovery flow path that recovers the liquid from the liquid ejection head to the first reservoir;
Equipped with
A liquid ejection apparatus, wherein a first connection portion between the liquid ejection head and the recovery flow passage is disposed at a higher position than a second connection portion between the liquid ejection head and the supply flow passage. a liquid ejection head that ejects liquid from nozzles provided on a nozzle surface;
a first reservoir section having an introduction section at an upper portion thereof through which the liquid contained in the liquid storage section can be introduced, and the liquid level fluctuates within a range lower than the nozzle surface;
a second storage portion that communicates with the first storage portion via a communication passage and to which the liquid is supplied from the first storage portion due to a head difference;
a supply flow path that supplies the liquid from the second reservoir to the liquid ejection head;
a recovery flow path that recovers the liquid from the liquid ejection head to the first reservoir;
A second valve capable of opening and closing the supply flow path;
Equipped with
A liquid ejection apparatus, wherein a first connection portion between the liquid ejection head and the recovery flow passage is disposed at a higher position than a second connection portion between the liquid ejection head and the supply flow passage. a liquid ejection head that ejects liquid from nozzles provided on a nozzle surface;
a first reservoir section having an introduction section at an upper portion thereof through which the liquid contained in the liquid storage section can be introduced, and the liquid level fluctuates within a range lower than the nozzle surface;
a second storage portion that communicates with the first storage portion via a communication passage and to which the liquid is supplied from the first storage portion due to a head difference;
a supply flow path that supplies the liquid from the second reservoir to the liquid ejection head;
a recovery flow path that recovers the liquid from the liquid ejection head to the first reservoir;
A third valve capable of opening and closing the recovery passage;
Equipped with
A liquid ejection apparatus, wherein a first connection portion between the liquid ejection head and the recovery flow passage is disposed at a higher position than a second connection portion between the liquid ejection head and the supply flow passage. 3. The liquid ejection device according to claim 1, further comprising a third valve capable of opening and closing the recovery passageway. 10. The method according to claim 1, further comprising:
Item 4. A liquid ejection device according to item 3 . 5. The liquid ejection device according to claim 3, further comprising a micro-pressure unit provided in the recovery flow path between the liquid ejection head and the third valve, the micro-pressure unit having a liquid chamber, a portion of which is made of a flexible material , and a pressure mechanism capable of pressurizing the flexible material from outside the liquid chamber. The pressurizing mechanism includes a pressurizing unit, an air chamber separated from the liquid chamber via the flexible member,
The liquid ejection device according to claim 6 , further comprising an air flow path that connects the pressurizing portion and the air chamber. A pressurizing unit that pressurizes the second storage unit;
a first valve capable of closing the communication passage when the pressurizing unit pressurizes the communication passage;
The liquid ejection device according to any one of claims 1 to 6, further comprising: a first valve capable of closing the communication passage;
The pressurizing unit pressurizes the second storage unit,
The liquid ejection device according to claim 7 , wherein the first valve closes the communication passage when the pressure is applied by the pressure applying portion. the first valve permits flow of the liquid from the first reservoir to the second reservoir;
10. The liquid ejection device according to claim 8, further comprising a check valve that limits the flow of the liquid from the second storage portion to the first storage portion. a liquid ejection head that ejects liquid from nozzles provided on a nozzle surface;
a first reservoir section having an introduction section at an upper portion thereof through which the liquid contained in the liquid storage section can be introduced, and the liquid level fluctuates within a range lower than the nozzle surface;
a second storage portion that communicates with the first storage portion via a communication passage and to which the liquid is supplied from the first storage portion due to a head difference;
a supply flow path that supplies the liquid from the second reservoir to the liquid ejection head;
A pressurizing unit that pressurizes the second storage unit;
a first valve capable of closing the communication passage when the pressurizing unit pressurizes the communication passage;
Equipped with
the first valve permits flow of the liquid from the first reservoir to the second reservoir;
A liquid ejection device comprising: a check valve that limits the flow of the liquid from the second storage portion to the first storage portion. The liquid ejection device according to claim 11 , further comprising a second valve capable of opening and closing the supply flow path. 13. The liquid ejection apparatus according to claim 11 , further comprising a recovery passageway that recovers the liquid from the liquid ejection head to the first storage section. The liquid ejection device according to claim 13 , further comprising a third valve capable of opening and closing the recovery passageway. A liquid ejection device according to claim 14, further comprising a micro-pressure unit that has a liquid chamber, a portion of which is made of a flexible material, and a pressure mechanism that can pressurize the flexible material from outside the liquid chamber, and is provided in the recovery flow path between the liquid ejection head and the third valve . 2. The pressure mechanism according to claim 1, wherein the pressure mechanism includes the pressure unit, an air chamber separated from the liquid chamber via the flexible member, and an air flow path connecting the pressure unit and the air chamber.
6. The liquid ejection apparatus according to claim 5 . 13. The method according to claim 12 , wherein a first connection portion between the liquid ejection head and the recovery flow passage is disposed at a higher position than a second connection portion between the liquid ejection head and the supply flow passage.
16. A liquid ejection apparatus according to any one of claims 1 to 16 . a liquid ejection head that ejects liquid from nozzles provided on a nozzle surface;
a first reservoir section having an introduction section at an upper portion thereof through which the liquid contained in the liquid storage section can be introduced, and the liquid level fluctuates within a range lower than the nozzle surface;
a second storage portion that communicates with the first storage portion via a communication passage and to which the liquid is supplied from the first storage portion due to a head difference;
a supply flow path that supplies the liquid from the second reservoir to the liquid ejection head;
a recovery flow path that recovers the liquid from the liquid ejection head to the first reservoir;
A pressurizing unit that pressurizes the second storage unit;
a first valve capable of closing the communication passage when the pressurizing unit pressurizes the communication passage;
A second valve capable of opening and closing the supply flow path;
A third valve capable of opening and closing the recovery passage;
a slight pressure applying unit including a liquid chamber, a portion of which is made of a flexible member, and a pressure applying mechanism capable of applying pressure to the flexible member from outside the liquid chamber, the slight pressure applying unit being provided in the recovery flow path between the liquid ejection head and the third valve;
A liquid ejection device comprising: 2. The pressure mechanism according to claim 1, wherein the pressure mechanism includes the pressure unit, an air chamber separated from the liquid chamber via the flexible member, and an air flow path connecting the pressure unit and the air chamber.
9. The liquid ejection apparatus according to claim 8 . 20. The liquid ejection apparatus according to claim 18, wherein a first connection portion between the liquid ejection head and the recovery flow passage is disposed at a higher position than a second connection portion between the liquid ejection head and the supply flow passage . the first valve permits flow of the liquid from the first reservoir to the second reservoir;
21. The liquid ejection device according to claim 18, further comprising a check valve that limits a flow of the liquid from the second storage portion to the first storage portion. 22. The liquid ejection apparatus according to claim 1 , wherein the liquid ejection head is disposed so that the nozzle surface is inclined relative to the horizontal.