JP2022109702A - Liquid circulating device, liquid discharging apparatus, and bubble exhausting method in liquid discharging apparatus - Google Patents

Abstract

To provide: a liquid circulating device capable of inhibiting liquid flowing portions from increasing; a liquid discharging apparatus; and a bubble exhausting method in the liquid discharging apparatus.SOLUTION: A liquid circulating device has: a supply flow path 28 through which a liquid is supplied from a liquid supply source that stores the liquid to a liquid ejecting head 23 that ejects the liquid; a collection flow path 29 through which the liquid collected from the liquid ejecting head 23 is returned to the supply flow path 28; and a liquid flowing portion 27 that causes the liquid to flow in a circulation flow path 26 including the supply flow path 28, the liquid ejecting head 23 and the collection flow path 29. An air capturing portion 45 capable of capturing bubbles is provided in at least one of the supply flow path 28 and the collection flow path 29. The air capturing portion 45 is disposed at a position higher than the position of the liquid ejecting head 23.SELECTED DRAWING: Figure 2

Description

The present invention relates to a liquid circulation device, a liquid ejection device, and a bubble discharging method for the liquid ejection device.

2. Description of the Related Art For example, Japanese Patent Laid-Open No. 2002-100000 discloses a recording apparatus, which is an example of a liquid ejection device that ejects ink, which is an example of a liquid, from a head unit, which is an example of a liquid ejection head, for printing. A recording apparatus includes an ink supply unit, which is an example of a liquid circulation device. The ink supply unit includes a supply channel for supplying ink from the sub-tank to the head unit, and a recovery channel for recovering the ink from the head unit to the sub-tank.

JP 2019-014154 A

Air bubbles may be mixed in the liquid. Air bubbles move with the flowing liquid. In the ink supply unit disclosed in Japanese Patent Laid-Open No. 2002-200010, if the circulation is stopped halfway, there is a risk that the bubbles will collect in the head. Therefore, a plurality of pumps are required for discharging bubbles.

A liquid circulating apparatus for solving the above-mentioned problems comprises: a supply channel for supplying the liquid from a liquid supply source containing the liquid to a liquid ejection head for ejecting the liquid; a recovery channel for returning to a channel; and a liquid flow section for causing the liquid to flow in a circulation channel including the supply channel, the liquid ejection head, and the recovery channel, wherein the supply channel and the At least one of the recovery channels is provided with an air capturing section capable of capturing air bubbles, and the air capturing section is provided at a position higher than the liquid ejection head.

A liquid ejection apparatus for solving the above-described problems includes a plurality of the liquid circulation apparatuses described above, the liquid ejection head for ejecting the liquid, and the plurality of the liquid circulation apparatuses having one common liquid flow section. , one of the liquid flow sections has an air pressurization section that supplies air to the plurality of downstream storage sections to pressurize the insides of the downstream storage sections, and the air pressurization section pressurizes the interiors of the plurality of downstream storage sections. Pressurization is possible at the same time.

A method for discharging air bubbles in a liquid ejection apparatus for solving the above-described problems includes a liquid ejection head for ejecting liquid, a supply channel for supplying the liquid from a liquid supply source containing the liquid to the liquid ejection head, and the liquid ejection. a recovery channel for returning the liquid recovered from the head to the supply channel; a liquid flow section for causing the liquid to flow in a circulation channel including the supply channel, the liquid ejection head, and the recovery channel; wherein at least one of the supply flow path and the recovery flow path is provided with an air capturing section capable of capturing air bubbles, and the air capturing section is arranged in the flow path more than the liquid ejection head. It is composed of a folded portion provided at a high position, and the folded portion is composed of an ascending flow path in which the liquid rises and a descending flow path provided downstream of the ascending flow path and in which the liquid descends. a first flow step of flowing the liquid by the liquid flow section until the bubbles existing in the liquid discharge head reach the ascending channel or the descending channel. a waiting step of waiting for the air trapping time in a state where the flow of the liquid is stopped; and a second flow step of causing the

1 is a perspective view showing an embodiment of a liquid ejection device; FIG. FIG. 2 is a schematic diagram showing an example of a liquid circulation device included in the liquid ejection device. 4 is a flow chart showing an example of a bubble discharge routine; The figure which shows the other example of an air capture|acquisition part.

Hereinafter, one embodiment of a liquid circulation device, a liquid ejection device, and a bubble discharging method will be described with reference to the drawings. A liquid ejecting apparatus is, for example, an inkjet printer that ejects ink, which is an example of a liquid, onto a medium such as paper for printing.

In the drawing, the direction of gravity is indicated by the Z-axis, and the directions along the horizontal plane are indicated by the X-axis and the Y-axis, assuming that the liquid ejection device 11 is placed on a horizontal plane. The X-axis, Y-axis, and Z-axis are orthogonal to each other.

[Structure of Liquid Ejecting Device 11]
As shown in FIG. 1, the liquid ejecting apparatus 11 includes a medium storage unit 13 capable of accommodating the medium 12, a stacker 14 receiving the printed medium 12, and an operation unit such as a touch panel for operating the liquid ejecting apparatus 11. and a portion 15. The liquid ejection device 11 may include an image reading section 16 that reads an image of a document, and an automatic feeding section 17 that feeds the document to the image reading section 16 .

The liquid ejection device 11 includes a control section 19 that controls various operations performed by the liquid ejection device 11 . The control unit 19 includes α: one or more processors that execute various processes according to a computer program, β: one or more dedicated hardware such as an application-specific integrated circuit that executes at least part of the various processes. ware circuit, or γ: a combination thereof. A processor includes a CPU and memory, such as RAM and ROM, which stores program code or instructions configured to cause the CPU to perform processes. Memory or computer-readable media includes any computer-readable media that can be accessed by a general purpose or special purpose computer.

As shown in FIG. 2 , the liquid ejection device 11 includes a liquid ejection head 23 that ejects liquid from nozzles 22 provided on a nozzle surface 21 and a liquid circulation device 24 . The liquid ejection device 11 may have a plurality of liquid circulation devices 24 . The liquid ejection device 11 of this embodiment has two liquid circulation devices 24 . The configuration of the two liquid circulation devices 24 is the same. Therefore, overlapping description is omitted by attaching the same reference numerals to the common configurations.

The liquid circulation device 24 includes a circulation flow path 26 and a liquid flowing section 27 that causes the liquid to flow within the circulation flow path 26 . The circulation channel 26 includes a supply channel 28 , a liquid ejection head 23 and a recovery channel 29 . The liquid ejection head 23 may have a first connection portion 31 to which the supply channel 28 is connected and a second connection portion 32 to which the recovery channel 29 is connected.

The supply channel 28 is a channel for supplying liquid from a liquid supply source 34 containing liquid to the liquid ejection head 23 . The recovery channel 29 is a channel for returning the liquid recovered from the liquid ejection head 23 to the supply channel 28 . A plurality of liquid circulators 24 may have one common liquid flow section 27 . The liquid flowing part 27 causes the liquid in the circulation channel 26 to flow in the circulation direction D. As shown in FIG.

A plurality of liquid circulation devices 24 may supply different types of liquid to the liquid ejection head 23 . For example, the liquid ejection device 11 may perform color printing by ejecting a plurality of colors of ink supplied from a plurality of liquid circulation devices 24 .

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

The liquid ejection device 11 may include a mounting portion 36 to which the liquid supply source 34 is detachably mounted. The liquid supply source 34 may include a storage chamber 37 that stores liquid, a lead-out portion 38 for leading out the liquid stored in the storage chamber 37, and a storage portion side valve 39 provided in the lead-out portion 38. good. The storage chamber 37 of this embodiment is a closed space that is not in communication with the atmosphere. The liquid supply source 34 before being attached to the attachment portion 36 may contain a larger amount of liquid than the volume of the circulation channel 26 .

The supply channel 28 has an upstream end connected to the liquid supply source 34 and a downstream end connected to the first connection portion 31 . The supply channel 28 may have an upstream storage portion 41 and a downstream storage portion 42 capable of storing the liquid supplied from the liquid supply source 34 . The downstream reservoir 42 is provided downstream of the upstream reservoir 41 in the supply channel 28 . That is, the downstream reservoir 42 is provided between the upstream reservoir 41 and the liquid ejection head 23 . The liquid circulation device 24 may include a valve 43 provided in the supply channel 28 between the upstream reservoir 41 and the downstream reservoir 42 .

The recovery channel 29 communicates between the liquid ejection head 23 and the upstream reservoir 41 . The recovery channel 29 has an upstream end connected to the second connection portion 32 and a downstream end connected to the upstream storage portion 41 . The recovery channel 29 is provided with an air trapping portion 45 capable of trapping air bubbles. The air capture section 45 is provided at a position higher than the liquid ejection head 23 . Specifically, the air capturing portion 45 is provided at a position higher than the liquid flow path provided in the liquid ejection head 23 . The air capturing portion 45 is provided at a position higher than the second connecting portion 32 where the recovery channel 29 in which the air capturing portion 45 is provided is connected to the liquid ejection head 23 .

The air trapping portion 45 may be composed of one or more folded portions CF. In this embodiment, the air trapping portion 45 is provided at the highest position in the supply channel 28 and the recovery channel 29, and is composed of one folded portion CF. The folded portion CF is composed of an ascending channel 45a through which the liquid flowing in the circulation direction D ascends and a descending channel 45b through which the liquid flowing in the circulation direction D descends. The descending channel 45b is provided downstream in the circulation direction D from the ascending channel 45a.

One liquid flow section 27 includes a pressurizing flow path 47 connected to each of the plurality of downstream reservoirs 42, an air pressurizing section 48 supplying air to the plurality of downstream reservoirs 42 via the pressurizing flow path 47, may have The air pressurizing section 48 pressurizes the inside of the downstream storage section 42 . The air pressurizing part 48 can simultaneously pressurize the insides of the plurality of downstream reservoirs 42 .

The air pressurizing unit 48 is, for example, a tube pump that sends out air by rotating while crushing a tube with a roller. A tube (not shown) included in the air pressurizing unit 48 has one end open and the other end connected to the pressurizing flow path 47 . The air pressurizing part 48 sends out the taken air to the pressurizing flow path 47 by being driven to rotate forward. The air pressurizing part 48 is driven in reverse so that the roller releases the tube, and the inside of the pressurizing flow path 47 and the inside of the downstream storage part 42 are communicated with the atmosphere.

The liquid circulation device 24 may include an atmosphere release passage 50 connected to the upstream reservoir 41 and an atmosphere release valve 51 provided in the atmosphere release passage 50 . The atmosphere release valve 51 is opened to open the atmosphere release passage 50 and communicate the upstream reservoir 41 with the atmosphere.

Next, the upstream reservoir 41 will be described. The upstream storage portion 41 has an introduction portion 60 into which the liquid contained in the liquid supply source 34 attached to the attachment portion 36 can be introduced. The upstream storage section 41 includes a device-side valve 61 provided in the introduction section 60, a first storage chamber 62 for storing liquid, a liquid amount sensor 63 for detecting the amount of liquid stored in the first storage chamber 62, A first gas-liquid separation membrane 64 that separates the first storage chamber 62 and the open air path 50 may be provided. The first gas-liquid separation membrane 64 is a membrane that allows gas to pass through but does not allow liquid to pass through.

The container-side valve 39 and the device-side valve 61 are opened when the liquid supply source 34 is attached to the attachment portion 36 , and remain open while the liquid supply source 34 is attached to the attachment portion 36 . maintain. When the liquid supply source 34 is attached to the attachment portion 36 , the device-side valve 61 is configured to open before the container-side valve 39 , thereby reducing the risk of liquid leaking from the liquid supply source 34 .

The introduction section 60 is provided above the upstream storage section 41 . The introduction part 60 of this embodiment is provided so as to penetrate through the ceiling 65 of the first storage chamber 62 . The lower end of the introduction part 60 is positioned below the ceiling 65 inside the first storage chamber 62 . The upper end of the introduction part 60 is located outside the first storage chamber 62 and above the ceiling 65 . The introduction section 60 is connected to the outlet section 38 included in the liquid supply source 34 by attaching the liquid supply source 34 to the attachment section 36 .

A lower end of the introduction portion 60 is located below the nozzle surface 21 . As a result, the first liquid level 66 of the liquid stored in the upstream reservoir 41 fluctuates in a range lower than the nozzle surface 21 . Specifically, the liquid in the liquid supply source 34 is supplied to the upstream reservoir 41 via the lead-out portion 38 and the lead-in portion 60 due to the hydraulic head. Air is introduced into the liquid supply source 34 from the upstream storage section 41 via the introduction section 60 and the discharge section 38 by the amount of the liquid supplied to the upstream storage section 41 . The first liquid level 66 rises by the amount of the supplied liquid. When the first liquid surface 66 reaches the lower end of the introduction section 60, the inflow of air from the upstream storage section 41 to the liquid supply source 34 is restricted. Since the storage chamber 37 is sealed, when the inflow of air is restricted, the pressure in the storage chamber 37 is reduced by the amount of the supplied liquid. When the negative pressure in the storage chamber 37 becomes higher than the head of the liquid in the storage chamber 37, the supply of liquid from the liquid supply source 34 to the upstream reservoir 41 is restricted.

The first liquid surface 66 descends as the liquid is supplied from the upstream reservoir 41 to the downstream reservoir 42 . When the first liquid level 66 descends and air flows into the storage chamber 37 via the introduction portion 60 and the discharge portion 38, the negative pressure in the storage chamber 37 decreases. When the negative pressure in the storage chamber 37 becomes smaller than the head of the liquid in the storage chamber 37 , liquid is supplied from the liquid supply source 34 to the upstream reservoir 41 . Therefore, while liquid is stored in the liquid supply source 34 , the first liquid level 66 is maintained at the standard position near the lower end of the introduction section 60 . When the liquid contained in the liquid supply source 34 is exhausted, the first liquid level 66 is positioned below the standard position.

The liquid level sensor 63 detects that the first liquid level 66 is positioned at the standard position, that the first liquid level 66 is positioned below the standard position, and that the first liquid level 66 is positioned above the standard position at the full position. may be detected. When the first liquid surface 66 is positioned at the full position, the upstream storage section 41 stores the maximum amount of liquid. When the liquid level sensor 63 detects that the first liquid level 66 is positioned below the standard position, the control section 19 determines that the liquid supply source 34 is empty, and instructs the user to replace the liquid supply source 34. may be instructed to

The standard position of the present embodiment is positioned above the position where the downstream end of the recovery channel 29 is connected in the first storage chamber 62 . Therefore, when the first liquid surface 66 is at the standard position, the liquid in the upstream reservoir 41 can be supplied to the liquid ejection head 23 via the recovery channel 29 .

Next, the downstream reservoir 42 will be described. The downstream storage section 42 may have a second storage chamber 68 that stores liquid and a second gas-liquid separation membrane 69 that separates the second storage chamber 68 from the pressurized flow path 47 . The second gas-liquid separation membrane 69 is, like the first gas-liquid separation membrane 64, a membrane that allows gas to pass through but does not allow liquid to pass through.

The downstream reservoir 42 is supplied with the liquid from the upstream reservoir 41 due to the head difference. The valve 43 may be configured with a check valve that allows the flow of liquid from the upstream reservoir 41 to the downstream reservoir 42 and restricts the flow of liquid from the downstream reservoir 42 to the upstream reservoir 41 . good. 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 downstream storage section 42 is at the same height as the first liquid level 66 . In other words, the second liquid surface 70 is maintained at a standard position that is approximately the same height as the lower end of the introduction portion 60 and fluctuates within a range lower than the nozzle surface 21 . The liquid in the liquid ejection head 23 is maintained at a negative pressure due to the head difference between the liquid in the upstream storage section 41 and the downstream storage section 42 . When the liquid is consumed in the liquid ejection head 23 , the liquid stored in the downstream reservoir 42 is supplied to the liquid ejection head 23 .

Valve 43 closes supply channel 28 when the pressure in downstream reservoir 42 is greater than the pressure in upstream reservoir 41 . Therefore, the valve 43 closes the supply channel 28 when the air pressure unit 48 pressurizes the inside of the downstream reservoir 42 .

[Bubble discharge routine]
Next, the bubble discharging method of the liquid ejection device 11 will be described with reference to the bubble discharging routine shown in FIG. Here, the order of steps in each control method can be arbitrarily changed without departing from the purpose of each control method. The controller 19 may execute the air bubble discharge routine at the timing when the air bubble discharge instruction is given. The control unit 19 may, for example, execute the bubble discharging routine after the circulation flow path 26 is filled with the liquid and after the power supply of the liquid ejection device 11 is turned on, or may periodically execute the bubble discharging routine. may be executed.

As shown in FIG. 3, in step S101, the controller 19 opens the upstream reservoir 41 to the atmosphere. In step S<b>102 , the control unit 19 causes the air pressurization unit 48 to pressurize the inside of the downstream reservoir 42 .

In step S103, the control unit 19 determines whether or not the first liquid level 66 is positioned at the full position. If the first liquid surface 66 is not located at the full position, step S103 becomes NO, and the control section 19 shifts the process to step S106. If the first liquid surface 66 is located at the full position, step S103 becomes YES, and the control unit 19 shifts the process to step S104. In step S104, the control unit 19 reversely drives the air pressurizing unit 48 to open the downstream storage unit 42 to the atmosphere.

In step S105, the controller 19 determines whether or not the first liquid level 66 has decreased to the standard position. If the first liquid level 66 is not positioned at the standard position, step S105 becomes NO, and the controller 19 waits until the first liquid level 66 is positioned at the standard position. If the first liquid level 66 is positioned at the standard position, step S105 becomes YES, and the control section 19 shifts the processing to step S102.

In step S<b>106 , the control unit 19 determines whether or not the liquid of the flow volume has been supplied from the downstream reservoir 42 . When the liquid supplied from the downstream storage section 42 is less than the flow capacity, step S106 becomes NO, and the control section 19 shifts the process to step S103. If the flow volume of the liquid has been supplied from the downstream storage section 42, step S106 becomes YES, and the control section 19 shifts the process to step S107.

In step S107, the control unit 19 reversely drives the air pressurizing unit 48 to open the downstream storage unit 42 to the atmosphere. In step S108, the controller 19 determines whether or not the downstream reservoir 42 has been pressurized a predetermined number of times. The predetermined number of times is, for example, the number of air capturing portions 45 plus one. In this embodiment, the predetermined number of times is two because the liquid circulating device 24 includes one air capturing portion 45 . If the number of times the downstream reservoir 42 has been pressurized is less than the predetermined number of times, step S108 becomes NO, and the control section 19 shifts the process to step S109.

In step S109, the control unit 19 determines whether or not the air capturing time has elapsed since the downstream storage unit 42 was opened to the atmosphere. If the air capture time has not elapsed, step S109 becomes NO, and the controller 19 waits until the air capture time has elapsed. When the air capture time has passed, step S109 becomes YES, and the control unit 19 shifts the process to step S102.

In step S108, when the number of times the downstream reservoir 42 has been pressurized after starting the bubble discharge routine reaches a predetermined number, step S108 becomes YES, and the controller 19 terminates the bubble discharge routine.

Next, the action when air bubbles are discharged will be described.
As shown in FIG. 3, the liquid circulator 24 discharges air bubbles from the circulation channel 26 by performing the first flow process, the standby process, and the second flow process in this order. Specifically, the liquid circulator 24 executes steps S102, S106, and S107 as the first flow process and the second flow process. The liquid circulation device 24 executes step S109 as a standby process.

As shown in FIG. 2, in the first flow step, bubbles existing in the liquid ejection head 23 flow the liquid by the liquid flow section 27 until they reach the ascending flow path 45a or the descending flow path 45b. Specifically, the liquid circulating device 24 pressurizes the inside of the downstream reservoir 42 by the air pressurizing unit 48 to push out the liquid in the downstream reservoir 42 and push the liquid in the circulation channel 26 in the circulation direction D. let it flow. At this time, the inside of the upstream reservoir 41 is open to the atmosphere. Therefore, the pressure in the downstream reservoir 42 becomes higher than the pressure in the upstream reservoir 41, and the valve 43 is closed.

The volume of the liquid to be flowed in the first flow step may be smaller than the air volume obtained by subtracting the volume of the liquid stored in the upstream reservoir 41 from the maximum volume that can be stored in the upstream reservoir 41 . The maximum capacity that can be stored in the upstream storage section 41 is the volume of liquid that is stored in the upstream storage section 41 when the first liquid level 66 is positioned at the full position. Therefore, the air volume is the volume of liquid that the upstream reservoir 41 can receive. In the case where the first fluidizing step causes fluid to flow in a volume smaller than the air volume, the position of the first liquid surface 66 when the first fluidizing step ends is below the full position.

The volume of liquid to be flowed in the first flowing step may be less than the volume of liquid stored in the downstream reservoir 42 before starting the first flowing step. The valve 43 of this embodiment closes when the pressure in the downstream reservoir 42 is higher than the pressure in the upstream reservoir 41 . Therefore, the supply of liquid from the upstream reservoir 41 to the downstream reservoir 42 is stopped during the first flow step. Therefore, by making the volume of the liquid supplied from the downstream storage section 42 in the first flow process smaller than the liquid stored in the downstream storage section 42, the supply of liquid to the downstream storage section 42 during the first flow process is reduced. becomes unnecessary.

The volume flowed in the first flow step may be larger than the volume from the liquid ejection head 23 to the air capturing section 45 . As a result, air bubbles accumulated in the liquid ejection head 23 are sent to the air trapping section 45 .

In the standby step, the flow of the liquid is stopped and the air capture time is waited. The air capture time is, for example, the time required for bubbles positioned in the ascending channel 45a and the descending channel 45b to move due to buoyancy and gather at an intermediate position between the ascending channel 45a and the descending channel 45b. Specifically, the air capture time is a time of several seconds to several tens of seconds. The air capture time may be a preset time, or may be the length and inclination of the ascending flow path 45a and the descending flow path 45b, the air temperature of the environment in which the liquid ejection device 11 is installed, and the temperature of the liquid. You may set by etc. For example, when the air temperature and the temperature of the liquid are high, the viscosity of the liquid decreases, the size of the bubbles increases, and the bubbles move easily. Therefore, the air capture time may be shortened as the length of the ascending flow path 45a and the descending flow path 45b is shorter, the inclination is greater, and the air temperature and the temperature of the liquid are higher.

In the standby process, the downstream reservoir 42 is opened to the atmosphere. Therefore, the pressure in both the upstream reservoir 41 and the downstream reservoir 42 becomes atmospheric pressure, and the valve 43 opens. When the first fluidizing step ends and the waiting step starts, the first liquid level 66 is positioned above the second liquid level 70 . The liquid in the upstream reservoir 41 is supplied to the downstream reservoir 42 by the head. In the standby process, the first liquid level 66 drops and the second liquid level 70 rises.

In the second flowing step, the liquid is caused to flow by the liquid flowing section 27 until the air bubbles captured by the air capturing section 45 are sent to the supply channel 28 . The volume of liquid to be flowed in the second flow step may be larger than the volume from the air capture section 45 to the upstream storage section 41 . As a result, the air bubbles collected in the air capturing portion 45 are sent to the supply channel 28 .

In the first fluidizing step and the second fluidizing step, the same volume of liquid may be fluidized. The volume to be flowed in each of the first fluidizing step and the second fluidizing step is larger than the volume from the liquid ejection head 23 to the air trapping portion 45 and the volume from the air trapping portion 45 to the upstream storage portion 41. It may be larger than the capacity of the other.

For example, in the standby process, if the air capture time is short relative to the time required for the first liquid level 66 to descend to the standard position, the first liquid level 66 will be positioned above the standard position at the start of the second flow process. I have something to do. If the second flow step is performed in this state, the first liquid level 66 may reach the full position before the air bubbles captured by the air capture section 45 are sent to the upstream storage section 41 . In this case, the control unit 19 may stop the second flow step and open the downstream reservoir 42 to the atmosphere. The control unit 19 may wait until the first liquid level 66 reaches the standard position before performing the second flow step.

Effects of the present embodiment will be described.
(1) The liquid flowing section 27 causes the liquid to flow within the circulation channel 26 including the supply channel 28 , the liquid ejection head 23 , and the recovery channel 29 . Since the air capturing section 45 is provided at a position higher than the liquid ejection head 23, the buoyancy of air bubbles can be used for capturing the air bubbles. The air capturing portion 45 is provided in at least one of the supply channel 28 and the recovery channel 29 . The liquid flowing section 27 can prevent the bubbles from gathering in the liquid ejection head 23 by causing the bubbles to flow to the air trapping section 45, so that the circulation can be stopped in the middle. Therefore, it is possible to discharge air bubbles through circulation without providing a plurality of liquid flowing portions 27 .

(2) The air trapping portion 45 is composed of a folded portion CF provided in the flow path. descent channel 45b that descends.

According to this configuration, the air capture portion 45 is configured by the folded portion CF provided in the flow path. The folded portion CF is composed of an ascending channel 45a through which the liquid ascends, and a descending channel 45b provided downstream of the ascending channel 45a and through which the liquid descends. Bubbles move upward due to buoyancy. Therefore, the air capturing section 45 can collect the air bubbles in the ascending flow path 45a and the air bubbles in the descending flow path 45b between the ascending flow path 45a and the descending flow path 45b. Therefore, the liquid circulation device 24 can realize the air capture section 45 with a simple configuration.

(3) The air capturing portion 45 may be provided at the highest position in the flow path.
According to this configuration, the air trapping portion 45 can easily move the air bubbles to the air trapping portion 45 by the buoyancy generated in the air bubbles, and can further suppress the gathering of the air bubbles in the liquid ejection head 23 when the circulation is stopped.

(4) The air capture section 45 may be provided in the recovery passageway 29 .
According to this configuration, the air capturing section 45 captures air bubbles downstream of the liquid ejection head 23 . Therefore, it is possible to prevent the air bubbles that have passed through the liquid ejection head 23 from returning to the liquid ejection head 23 .

(5) The supply channel 28 has an upstream storage portion 41 and a downstream storage portion 42 capable of storing liquid, and the downstream storage portion 42 is provided downstream of the upstream storage portion 41 in the supply channel 28, The path 29 may communicate the liquid ejection head 23 and the upstream reservoir 41 . According to this configuration, the liquid circulation device 24 can collect air bubbles in the upstream reservoir 41 .

(6) The volume of liquid flowed by the liquid flow section 27 at one time may be smaller than the air volume obtained by subtracting the volume of liquid stored in the upstream storage section 41 from the maximum volume that can be stored in the upstream storage section 41. . According to this configuration, the volume of liquid flowed by the liquid flow section 27 at one time is smaller than the air volume of the upstream storage section 41 . That is, the volume of liquid that flows into the upstream storage section 41 as the liquid flow section 27 causes the liquid to flow is smaller than the air volume. Therefore, it is possible to prevent the liquid from overflowing from the upstream reservoir 41 .

(7) The volume of liquid flowed by the liquid flowing section 27 at one time may be smaller than the volume of liquid retained by the downstream storage section 42 .
For example, if the liquid flowing portion 27 causes the liquid to flow in a volume larger than the volume of the liquid stored in the downstream storage portion 42 , air may be supplied from the downstream storage portion 42 . In this respect, according to this configuration, the volume of the liquid that the liquid flow section 27 makes flow at one time is smaller than the volume of the liquid that the downstream storage section 42 stores. Therefore, the air can be easily retained in the downstream reservoir 42 .

(8) The supply channel 28 is further provided with a valve 43 , which allows the liquid to flow from the upstream reservoir 41 to the downstream reservoir 42 and allows the liquid to flow from the downstream reservoir 42 to the upstream reservoir 41 . may restrict the flow of liquid to the According to this configuration, the valve 43 allows the flow of liquid from the upstream reservoir 41 to the downstream reservoir 42 and restricts the flow of liquid from the downstream reservoir 42 to the upstream reservoir 41 . Therefore, for example, the supply of liquid from the upstream reservoir 41 to the downstream reservoir 42 and the supply of liquid from the downstream reservoir 42 to the liquid ejection head 23 are performed by changing the pressure in the downstream reservoir 42 . can be done.

(9) The volume of liquid flowed by the liquid flow section 27 at one time is the volume from the liquid ejection head 23 to the air trapping section 45 or the volume from the air trapping section 45 to the supply channel 28, whichever is larger. may be greater than the capacity of According to this configuration, the liquid flow section 27 flows a larger volume of liquid than the volume from the liquid ejection head 23 to the air capturing section 45 and the volume from the air capturing section 45 to the supply channel 28 . Therefore, it is possible to reduce the risk of bubbles remaining between the liquid ejection head 23 and the air trapping portion 45 or between the air trapping portion 45 and the supply channel 28 .

(10) The liquid ejection device 11 has a plurality of the liquid circulation devices 24 described above, and includes a liquid ejection head 23 for ejecting liquid. The plurality of liquid circulation devices 24 are provided with one common liquid flow section 27, and the one liquid flow section 27 supplies air to the plurality of downstream reservoirs 42 to pressurize the insides of the downstream reservoirs 42. A pressure unit 48 is provided, and the air pressurization unit 48 can pressurize the insides of a plurality of downstream reservoirs 42 at the same time. According to this configuration, the liquid flowing section 27 has the air pressurizing section 48 . The air pressurizing part 48 can pressurize a plurality of downstream reservoirs 42 at the same time. Therefore, the plurality of liquid circulators 24 can flow the liquid in each liquid circulator 24 by one common liquid flow section 27 . Therefore, the number of parts can be reduced as compared with the case where the plurality of liquid circulating devices 24 are individually provided with the liquid flowing portions 27 .

(11) In the bubble discharging method of the liquid ejection device 11 , the liquid ejection device 11 includes the liquid ejection head 23 , the liquid flow section 27 , the supply channel 28 and the recovery channel 29 . The liquid ejection head 23 ejects liquid. The supply channel 28 supplies liquid to the liquid ejection head 23 from a liquid supply source 34 containing liquid. The recovery channel 29 returns the liquid recovered from the liquid ejection head 23 to the supply channel 28 . The liquid flow section 27 causes the liquid to flow within the circulation flow path including the supply flow path 28 , the liquid ejection head 23 and the recovery flow path 29 . At least one of the supply flow path 28 and the recovery flow path 29 is provided with an air capture section 45 capable of capturing air bubbles, and the air capture section 45 is positioned higher than the liquid ejection head 23 in the flow path. It is composed of the provided folded portion CF. The folded portion CF is composed of an ascending channel 45a through which the liquid ascends, and a descending channel 45b provided downstream of the ascending channel 45a and through which the liquid descends. The bubble discharging method of the liquid ejection device 11 includes a first flow process, a standby process, and a second flow process. In the first flow step, the liquid is caused to flow by the liquid flow section 27 until bubbles existing in the liquid ejection head 23 reach the ascending channel 45a or the descending channel 45b. The standby step waits for the air capture time while the liquid flow is stopped. In the second flowing step, the liquid is caused to flow by the liquid flowing section 27 until the air bubbles captured by the air capturing section 45 are sent to the supply channel 28 . According to this method, the same effect as that of the liquid circulation device 24 can be obtained.

(12) In the bubble discharging method of the liquid ejection device 11, the supply channel 28 includes an upstream reservoir 41 connected to the recovery channel 29 and capable of storing liquid, and an upstream reservoir 41 provided downstream of the upstream channel to store the liquid. and a possible downstream reservoir 42 . The volume of liquid to be flowed in each step of the first fluidizing step and the second fluidizing step is less than the air volume obtained by subtracting the volume of liquid stored in the upstream reservoir 41 from the maximum volume that can be stored in the upstream reservoir 41. may

According to this configuration, the volume of liquid flowed by the liquid flow section 27 at one time is smaller than the air volume of the upstream storage section 41 . That is, the volume of liquid that flows into the upstream storage section 41 as the liquid flow section 27 causes the liquid to flow is smaller than the air volume. Therefore, it is possible to prevent the liquid from overflowing from the upstream reservoir 41 .

(13) The volume of liquid to be flowed in each step of the first flowing step and the second flowing step may be smaller than the volume of liquid stored in the downstream reservoir 42 before starting each step.
For example, if the liquid flowing portion 27 causes the liquid to flow in a volume larger than the volume of the liquid stored in the downstream storage portion 42 , air may be supplied from the downstream storage portion 42 . In this respect, according to this configuration, the volume of the liquid that the liquid flow section 27 makes flow at one time is smaller than the volume of the liquid that the downstream storage section 42 stores. Therefore, the air can be easily retained in the downstream reservoir 42 .

(14) The volume of the liquid to be flowed in each of the first flow process and the second flow process is the volume from the liquid ejection head 23 to the air trapping section 45 and the volume from the air trapping section 45 to the upstream storage section 41. , may be larger than the larger capacity.

According to this configuration, the liquid flow section 27 flows a larger volume of liquid than the volume from the liquid ejection head 23 to the air capturing section 45 and the volume from the air capturing section 45 to the supply channel 28 . Therefore, it is possible to reduce the risk of bubbles remaining between the liquid ejection head 23 and the air trapping portion 45 or between the air trapping portion 45 and the supply channel 28 .

This embodiment can be implemented with the following modifications. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
- As shown in FIG. 4, the air capturing portion 45 may be configured by, for example, a plurality of folded portions CF. The air capturing portion 45 shown in FIG. 4 is composed of two folded portions CF. As a result, the air trapping portion 45 can trap air bubbles more efficiently than when there is only one folded portion CF.

- As shown in FIG. 4 , the liquid ejection device 11 may include one liquid circulation device 24 . The liquid ejection device 11 may perform monochrome printing by ejecting ink of one color, for example.
- As shown in FIG. 4, the liquid ejection head 23 may be arranged so that the nozzle surface 21 is inclined with respect to the horizontal. The liquid ejection head 23 may perform printing by ejecting liquid onto the medium 12 in an inclined posture. The liquid ejection head 23 may be provided so as to be able to change its posture between a horizontal posture in which the nozzle surface 21 is horizontal and an inclined posture. One of the first connection portion 31 and the second connection portion 32 may be positioned higher than the other. The air trapping portion 45 may be provided in a channel connected to the higher one of the first connection portion 31 and the second connection portion 32 . For example, the second connection portion 32 may be positioned higher than the first connection portion 31 and the air capturing portion 45 may be provided in the recovery channel 29 connected to the second connection portion 32 .

・The air acquisition time may be longer than the time required for the first liquid level 66 to descend from the full position to the standard position, or the control unit 19 may set the first liquid level 66 to the standard position after the first liquid level 66 has A two-flow process may be performed. That is, the control section 19 may start the second flow step with the first liquid level 66 and the second liquid level 70 positioned at the standard positions.

- The liquid ejection head 23 may have a plurality of pressure chambers individually communicating with the plurality of nozzles 22, a common liquid chamber communicating with the plurality of pressure chambers, and a filter chamber accommodating a filter. The first connection portion 31 and the second connection portion 32 are connected to at least one of the pressure chamber, common liquid chamber, and filter chamber. For example, when the first connection portion 31 and the second connection portion 32 are connected to the filter chamber, the liquid ejection device 11 causes the liquid to flow so that air bubbles captured by the filter are collected together with the liquid in the upstream storage portion 41 . can be done. The liquid ejecting apparatus 11 may discharge air bubbles when the liquid ejecting head 23 is filled with air bubbles.

- The liquid level sensor 63 may detect that the first liquid level 66 is positioned at the end position below the standard position. When the liquid level sensor 63 detects that the first liquid level 66 is positioned at the end position, the control section 19 may notify that the upstream storage section 41 is empty. The end position is the total amount of liquid stored in the upstream storage section 41 and the downstream storage section 42 when the first liquid level 66 and the second liquid level 70 are positioned at the end position, which is required for printing one medium 12. With more than the amount of liquid, printing on one medium 12 can be completed.

- The upstream storage part 41 and the downstream storage part 42 may be configured integrally.
- A diaphragm pump, a piston pump, a gear pump, or the like may be used as the air pressurizing unit 48 .

- The introduction part 60 and the lead-out part 38 may be provided respectively. For example, one flow path may flow liquid from liquid supply 34 to upstream reservoir 41 and another flow path may flow air from upstream reservoir 41 to liquid supply 34 .

- The liquid ejection device 11 may be provided with an atmosphere opening path 50 for opening the downstream reservoir 42 to the atmosphere, separately from the pressurization path 47 .
- The plurality of liquid circulators 24 may be individually provided with the liquid flow section 27 .

- The liquid flowing section 27 may include a plurality of valves provided in the pressurizing flow path 47 . A plurality of valves may be provided to individually correspond to the plurality of downstream reservoirs 42 . The control unit 19 may individually pressurize the inside of the downstream reservoir 42 by controlling the driving of the plurality of valves and the air pressurization unit 48 .

- The valve 43 may be opened and closed under the control of the controller 19 . The control unit 19 may close the valve 43 when the liquid flow unit 27 pressurizes the inside of the downstream reservoir 42 and open the valve 43 when supplying the liquid from the upstream reservoir 41 to the downstream reservoir 42 .

The volume of the liquid flowed by the liquid flow section 27 at one time is the larger of the volume from the liquid ejection head 23 to the air capturing section 45 and the volume from the air capturing section 45 to the supply channel 28. It may be below. For example, if the volume of the liquid flowed by the liquid flow section 27 at one time is equal to or less than the volume from the liquid ejection head 23 to the air trapping section 45, the air bubbles sent out from the liquid ejection head 23 reach the air trapping section 45. There is a risk that it will not. In this case, the air trapping time may be lengthened to wait until the air bubbles move to the air trapping portion 45 due to buoyancy. For example, if the volume of liquid flowed by the liquid flow section 27 at one time is equal to or less than the volume from the air capturing section 45 to the supply channel 28, the air bubbles sent from the air capturing section 45 do not reach the supply channel 28. There is fear. In this case, the circulation channel 26 downstream of the position where the bubbles reach may be provided at a position higher than the position where the bubbles reach, so that the bubbles move to the supply channel 28 by buoyancy.

- The volume of the liquid flowed by the liquid flow section 27 at one time may be greater than or equal to the volume of the liquid stored in the downstream storage section 42 . For example, the liquid flow section 27 may flow the liquid in the circulation channel 26 by supplying the liquid to the downstream storage section 42 . The volume of liquid flowed by the liquid flow section 27 at one time may be equal to or greater than the air volume of the upstream storage section 41 . The liquid flowing section 27 may be a pump provided in the supply channel 28 between the upstream storage section 41 and the downstream storage section 42 and supplying the liquid from the upstream storage section 41 to the downstream storage section 42 .

The recovery channel 29 may be connected to a position different from the upstream reservoir 41 as long as the supply channel 28 is upstream of the valve 43 .
The air trapping section 45 may be provided in the supply channel 28 as long as it is provided at a position higher than the liquid ejection head 23 . Specifically, the air capture portion 45 may be provided at a position higher than the first connection portion 31 in the supply channel 28 . When the air capturing portion 45 is provided in the supply channel 28 , the liquid flowing portion 27 has a capacity of the circulation channel 26 from the downstream storage portion 42 to the air capturing portion 45 and a capacity of the circulation channel 26 from the air capturing portion 45 to the upstream storing portion 41 . Of the volume of the circulation channel 26 and the volume of the larger one, more liquid may flow at once.

- The liquid circulation device 24 may include a plurality of air traps 45 . A plurality of air capturing portions 45 may be provided in the recovery channel 29 . A plurality of air traps 45 may be provided in the supply channel 28 . The air capture section 45 may be provided in both the supply channel 28 and the recovery channel 29 . When the liquid circulating device 24 has a plurality of air traps 45, the bubble discharging method may interrupt the second flowing step and perform a standby step. For example, when the liquid circulating device 24 includes one air capturing portion 45 provided in the supply channel 28 and one air capturing portion 45 provided in the recovery channel 29, the supply channel 28 is Air bubbles may be sent to the air trapping portion 45 provided in the air trapping portion 45, and the air trapping time may be waited for the air trapping portion 45 to collect the bubbles. In the second flow step, after the air bubbles accumulated in the air trapping section 45 provided in the supply channel 28 are sent to the air trapping section 45 provided in the recovery passageway 29, the air trapping time is waited. may be sent to the upstream reservoir 41 .

- The air capturing portion 45 may be located at a position different from the highest position in the circulation channel 26 .
- The air capture unit 45 may include a filter that captures air bubbles.

・Bubbles include not only bubble-like air but also air formed by a plurality of bubble-like air.
- The liquid ejection device 11 may be a liquid ejection device 11 that ejects or ejects a liquid other than ink. The state of the liquid ejected from the liquid ejecting apparatus 11 in the form of minute droplets includes granular, tear-like, and thread-like trailing liquid. The liquid referred to here may be any material as long as it can be ejected from the liquid ejection device 11 . For example, the liquid may be in a state when the substance is in a liquid phase, such as a high or low viscosity liquid, sol, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals, It is intended to include fluids such as metal melts. The term "liquid" includes not only a liquid as one state of a substance, but also a solution, dispersion, or mixture of particles of a functional material made of a solid substance such as a pigment or metal particles dissolved in a solvent. Typical examples of the liquid include ink and liquid crystal as described in the above embodiments. Here, the ink includes general water-based inks, oil-based inks, gel inks, hot-melt inks, and various other liquid compositions. Specific examples of the liquid ejection device 11 include, for example, liquid crystal displays, electroluminescence displays, surface-emitting displays, and liquids containing dispersed or dissolved materials such as electrode materials and coloring materials used in the manufacture of color filters. There is a device to The liquid ejection device 11 may be a device that ejects a bioorganic material used for biochip manufacturing, a device that is used as a precision pipette and ejects a sample liquid, a printing device, a microdispenser, or the like. The liquid ejection device 11 is made of a transparent material such as an ultraviolet curable resin to form a device that ejects lubricating oil pinpointly to a precision machine such as a watch or a camera, a micro hemispherical lens used in an optical communication device, an optical lens, or the like. It may be a device that discharges the resin liquid onto the substrate. The liquid ejection device 11 may be a device that ejects an etchant such as acid or alkali for etching a substrate or the like.

The technical ideas and effects obtained from the above-described embodiments and modifications will be described below.
(A) a supply channel that supplies liquid from a liquid supply source that stores liquid to a liquid ejection head that ejects liquid; a recovery channel that returns liquid recovered from the liquid ejection head to the supply channel; and a liquid flow section that causes liquid to flow within a circulation flow path including the flow path, the liquid ejection head, and the recovery flow path. At least one of the supply flow path and the recovery flow path is provided with an air capturing section capable of capturing air bubbles, and the air capturing section is provided at a position higher than the liquid ejection head.

According to this configuration, the liquid flow section causes the liquid to flow within the circulation flow path including the supply flow path, the liquid ejection head, and the recovery flow path. Since the air trapping section is provided at a position higher than the liquid ejection head, the buoyancy of the air bubbles can be used to trap the air bubbles. The air capturing portion is provided in at least one of the supply channel and the recovery channel. The liquid flowing section makes bubbles flow to the air trapping section, thereby suppressing the collection of air bubbles in the liquid ejection head, so that the circulation can be stopped halfway. Therefore, it is possible to discharge air bubbles through circulation without providing a plurality of liquid flowing parts.

(B) The air trapping portion is configured by a folded portion provided in the flow path, and the folded portion includes an ascending flow path through which the liquid rises and a downstream side of the ascending flow path, and the liquid may be configured by a descending flow path in which the is descending.

According to this configuration, the air capture portion is configured by the folded portion provided in the flow path. The folded portion is composed of an ascending channel through which the liquid ascends and a descending channel provided downstream of the ascending channel through which the liquid descends. Bubbles move upward due to buoyancy. Therefore, the air capturing section can collect air bubbles in the ascending channel and air bubbles in the descending channel between the ascending channel and the descending channel. Therefore, the liquid circulating device can realize the air capturing section with a simple configuration.

(C) The air capturing portion may be composed of a plurality of the folded portions.
According to this configuration, the air capturing portion can capture air bubbles more efficiently than when there is only one folded portion.

(D) The air capturing portion may be provided at the highest position in the flow path.
According to this configuration, the air trapping section can easily move the air bubbles to the air trapping section by the buoyancy generated in the air bubbles, and can further suppress the gathering of the air bubbles in the liquid ejection head when the circulation is stopped.

(E) The air capture section may be provided in the recovery channel.
According to this configuration, the air capturing section captures air bubbles downstream of the liquid ejection head. Therefore, it is possible to prevent bubbles that have passed through the liquid ejection head from returning to the liquid ejection head.

(F) The supply channel has an upstream storage portion and a downstream storage portion capable of storing the liquid, and the downstream storage portion is provided downstream from the upstream storage portion in the supply channel, and the recovery flow is A path may communicate the liquid ejection head and the upstream reservoir. According to this configuration, the liquid circulator can collect air bubbles in the upstream reservoir.

(G) The volume of the liquid flowed by the liquid flowing portion at one time is even less than the air volume obtained by subtracting the volume of the liquid stored in the upstream storage portion from the maximum volume that can be stored in the upstream storage portion. good.

According to this configuration, the volume of liquid flowed by the liquid flow section at one time is smaller than the air volume of the upstream storage section. That is, the volume of liquid that flows into the upstream storage section as the liquid flowing section causes the liquid to flow is smaller than the air volume. Therefore, it is possible to prevent the liquid from overflowing from the upstream reservoir.

(H) The volume of the liquid flowed by the liquid flowing section at one time may be smaller than the volume of the liquid stored in the downstream storage section.
For example, if the liquid flowing section causes the liquid to flow in a volume larger than the volume of the liquid stored in the downstream storage section, air may be supplied from the downstream storage section. In this regard, according to this configuration, the volume of the liquid that the liquid flowing section causes to flow at one time is smaller than the volume of the liquid that is stored in the downstream storage section. Therefore, it is possible to easily retain air in the downstream reservoir.

(I) further comprising a valve provided in the supply channel, the valve permitting the flow of the liquid supplied from the upstream reservoir to the downstream reservoir, and from the downstream reservoir to the upstream reservoir; may restrict the flow of liquid to the

With this arrangement, the valve allows liquid flow from the upstream reservoir to the downstream reservoir and restricts liquid flow from the downstream reservoir to the upstream reservoir. Therefore, for example, the supply of liquid from the upstream reservoir to the downstream reservoir and the supply of liquid from the downstream reservoir to the liquid ejection head can be performed by changing the pressure in the downstream reservoir.

(J) The volume of the liquid flowed by the liquid flowing section at one time is larger than the volume from the liquid ejection head to the air capturing section and the volume from the air capturing section to the supply channel. It may be larger than the capacity of the other.

According to this configuration, the liquid flowing section causes liquid to flow with a volume larger than the capacity from the liquid ejection head to the air capturing section and the capacity from the air capturing section to the supply channel. Therefore, it is possible to reduce the possibility that air bubbles remain between the liquid ejection head and the air capturing portion or between the air capturing portion and the supply channel.

(K) A liquid ejection device has a plurality of the liquid circulation devices described above, and includes the liquid ejection head for ejecting the liquid. The plurality of liquid circulators includes one common liquid flow section, and the one liquid flow section is an air pressurization section that supplies air to the plurality of downstream reservoirs to pressurize the insides of the downstream reservoirs. and the air pressurizing section can simultaneously pressurize the interiors of the plurality of downstream reservoirs.

According to this configuration, the liquid flowing section has the air pressurizing section. The air pressurizing section can simultaneously pressurize a plurality of downstream reservoirs. Therefore, a plurality of liquid circulators can flow the liquid in each liquid circulator by one common liquid flow section. Therefore, it is possible to reduce the number of parts compared to the case where a plurality of liquid circulators are individually provided with liquid flow sections.

(L) In a method for discharging bubbles in a liquid ejection device, a liquid ejection head for ejecting liquid, a supply channel for supplying the liquid from a liquid supply source containing the liquid to the liquid ejection head, and a recovery channel for returning the recovered liquid to the supply channel; and a liquid flow section for causing the liquid to flow within a circulation channel including the supply channel, the liquid ejection head, and the recovery channel. and an air trapping part capable of trapping air bubbles is provided in at least one of the supply flow path and the recovery flow path, and the air trapping part is positioned higher than the liquid ejection head in the flow path. The folded portion is composed of an ascending flow path in which the liquid rises and a descending flow path provided downstream of the ascending flow path and in which the liquid descends. A method for discharging air bubbles in an ejection device, comprising: a first flowing step of flowing the liquid by the liquid flowing portion until bubbles existing in the liquid ejection head reach the ascending channel or the descending channel; a standby step of waiting for an air capture time while stopping the flow of the liquid; and a two-flow process. According to this method, it is possible to obtain the same effects as the above liquid circulation device.

(M) Bubble Ejection Method for Liquid Ejecting Apparatus The supply channel includes an upstream storage part connected to the recovery channel and capable of storing the liquid, and an upstream storage part provided downstream of the ascending channel and capable of storing the liquid. and a downstream reservoir. The volume of the liquid to be flowed in each step of the first flowing step and the second flowing step is an air volume obtained by subtracting the volume of the liquid stored in the upstream reservoir from the maximum volume that can be stored in the upstream reservoir. may be less than

According to this configuration, the volume of liquid flowed by the liquid flow section at one time is smaller than the air volume of the upstream storage section. That is, the volume of liquid that flows into the upstream storage section as the liquid flowing section causes the liquid to flow is smaller than the air volume. Therefore, it is possible to prevent the liquid from overflowing from the upstream reservoir.

(N) The volume of the liquid to be flowed in each step of the first flowing step and the second flowing step may be smaller than the volume of the liquid stored in the downstream reservoir before each step is started. .
For example, if the liquid flowing section causes the liquid to flow in a volume larger than the volume of the liquid stored in the downstream storage section, air may be supplied from the downstream storage section. In this regard, according to this configuration, the volume of the liquid that the liquid flowing section causes to flow at one time is smaller than the volume of the liquid that is stored in the downstream storage section. Therefore, it is possible to easily retain air in the downstream reservoir.

(O) The volume of the liquid to be flowed in each of the first flowing step and the second flowing step is the volume from the liquid ejection head to the air capturing section and the volume from the air capturing section to the upstream storage section. and the capacity of the larger one.

According to this configuration, the liquid flowing section causes liquid to flow with a volume larger than the capacity from the liquid ejection head to the air capturing section and the capacity from the air capturing section to the supply channel. Therefore, it is possible to reduce the possibility that air bubbles remain between the liquid ejection head and the air capturing portion or between the air capturing portion and the supply channel.

DESCRIPTION OF SYMBOLS 11... Liquid ejection apparatus 12... Medium 13... Medium accommodating part 14... Stacker 15... Operation part 16... Image reading part 17... Automatic feeding part 19... Control part 21... Nozzle surface 22... Nozzle 23 Liquid ejection head 24 Liquid circulator 26 Circulation channel 27 Liquid flow section 28 Supply channel 29 Recovery channel 31 First connection 32 Second connection Parts 34 Liquid supply source 36 Mounting part 37 Storage chamber 38 Derivation part 39 Storage part side valve 41 Upstream storage part 42 Downstream storage part 43 Valve 45 Air capture Part 45a... Ascending flow path 45b... Down flow path 47... Pressurizing flow path 48... Air pressurizing part 50... Atmosphere release path 51... Atmosphere release valve 60... Introduction part 61... Apparatus 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 surface, CF ... folded portion, D ... circulation direction.

Claims (15)

a supply channel for supplying the liquid from a liquid supply source containing the liquid to a liquid ejection head for ejecting the liquid;
a recovery channel for returning the liquid recovered from the liquid ejection head to the supply channel;
a liquid flow section that causes the liquid to flow within a circulation flow path including the supply flow path, the liquid ejection head, and the recovery flow path;
At least one of the supply channel and the recovery channel is provided with an air capture section capable of capturing air bubbles,
The air trapping section is provided at a position higher than the liquid ejection head.
A liquid circulation device characterized by: The air capture portion is configured by a folded portion provided in the flow path,
The folded portion is composed of an ascending flow path in which the liquid rises and a descending flow path provided downstream of the ascending flow path and in which the liquid descends.
2. The liquid circulation system according to claim 1, characterized in that: The air capturing portion is composed of a plurality of the folded portions,
3. The liquid circulation system according to claim 2, characterized in that: The air trap is provided at the highest position in the flow path,
4. The liquid circulation device according to any one of claims 1 to 3, characterized in that: wherein the air capture unit is provided in the recovery channel;
5. The liquid circulation device according to any one of claims 1 to 4, characterized in that: The supply channel has an upstream storage section and a downstream storage section capable of storing the liquid,
The downstream reservoir is provided downstream from the upstream reservoir in the supply channel,
the recovery channel communicates the liquid ejection head and the upstream storage section;
6. The liquid circulation device according to any one of claims 1 to 5, characterized in that: The volume of the liquid flowed by the liquid flowing section at one time is smaller than the air volume obtained by subtracting the volume of the liquid stored in the upstream storage section from the maximum volume that can be stored in the upstream storage section.
7. The liquid circulation system according to claim 6, characterized in that: The volume of the liquid flowed by the liquid flowing section at one time is smaller than the volume of the liquid stored in the downstream storage section.
8. The liquid circulator according to claim 6 or 7, characterized in that: further comprising a valve provided in the supply channel,
the valve permits flow of the liquid from the upstream reservoir to the downstream reservoir and restricts flow of the liquid from the downstream reservoir to the upstream reservoir;
The liquid circulator according to any one of claims 6 to 8, characterized in that: The volume of the liquid flowed by the liquid flow section at one time is the larger of the volume from the liquid ejection head to the air capturing section and the volume from the air capturing section to the supply channel. more than
6. The liquid circulator according to claim 5, characterized in that: Having a plurality of liquid circulation devices according to any one of claims 6 to 9,
comprising the liquid ejection head for ejecting the liquid;
a plurality of the liquid circulation devices having one common liquid flowing section,
one of the liquid flowing parts has an air pressurizing part that supplies air to the plurality of downstream reservoirs to pressurize the inside of the downstream reservoirs;
The air pressurizing unit can simultaneously pressurize a plurality of the downstream reservoirs.
A liquid ejection device characterized by: a liquid ejection head for ejecting liquid; a supply channel for supplying the liquid from a liquid supply source containing the liquid to the liquid ejection head; and a recovery for returning the liquid recovered from the liquid ejection head to the supply channel. a flow path, and a liquid flow section that causes the liquid to flow in a circulation flow path including the supply flow path, the liquid ejection head, and the recovery flow path, wherein the supply flow path and the recovery flow path At least one of the flow paths is provided with an air trap capable of trapping air bubbles, and the air trap is composed of a folded portion provided at a position higher than the liquid ejection head in the flow path. Part is a bubble discharging method for a liquid ejecting device configured by an ascending flow path in which the liquid rises and a descending flow path provided downstream of the rising flow path and in which the liquid descends,
a first flowing step of flowing the liquid by the liquid flowing portion until bubbles existing in the liquid ejection head reach the ascending channel or the descending channel;
a standby step of waiting for an air capturing time while the flow of the liquid is stopped;
a second flowing step of flowing the liquid by the liquid flowing section until the air bubbles captured by the air capturing section are sent to the supply channel;
A bubble discharging method for a liquid ejection device, comprising: The supply channel has an upstream storage part connected to the recovery channel and capable of storing the liquid, and a downstream storage part provided downstream of the ascending channel and capable of storing the liquid,
The volume of the liquid to be flowed in each step of the first flowing step and the second flowing step is an air volume obtained by subtracting the volume of the liquid stored in the upstream reservoir from the maximum volume that can be stored in the upstream reservoir. less than
13. The method for discharging air bubbles in a liquid ejection device according to claim 12, wherein: The volume of the liquid to be flowed in each step of the first flowing step and the second flowing step is smaller than the volume of the liquid stored in the downstream reservoir before starting each step,
14. The method for discharging air bubbles from a liquid ejection device according to claim 13, wherein: The volume of the liquid to be flowed in each of the first flowing step and the second flowing step is the volume from the liquid ejection head to the air capturing section and the volume from the air capturing section to the upstream storage section. , greater than the larger capacity,
15. The bubble discharging method for a liquid ejection device according to claim 13 or 14, characterized in that:

Images