JP7255220B2 - liquid injector - Google Patents

Description

The present invention relates to a liquid ejecting apparatus such as a printer.

2. Description of the Related Art As an example of a liquid ejecting apparatus, there is an inkjet printer that performs printing by ejecting ink, which is an example of a liquid, from nozzles opening in a liquid ejecting head. In such a printer, in order to prevent the ink from leaking from the nozzles and to prevent the air from being drawn in from the nozzles when the ink is circulated, the pressure in the vicinity of the nozzles of the liquid jet head is adjusted to an appropriate value. It is desirable to keep

For example, the printer disclosed in Japanese Patent Application Laid-Open No. 2002-200000 uses a preset arithmetic expression based on the pressure detected from ink tanks connected to the liquid jet head and provided on the upstream side and the downstream side of the ink circulation system. It has a calculation means for obtaining the pressure. Further, in the printer of Patent Document 1, the value Y obtained by the calculation means is compared with a reference value in the pressure determination means, and it is determined whether the pressure is positive or negative with respect to the reference value. In the printer disclosed in Patent Document 1, a pump is connected to the ink circulation system, and the negative pressure value for the nozzles is increased when it is determined that the pressure is positive with respect to the reference value. As a result, the printer disclosed in Japanese Patent Application Laid-Open No. 2002-200014 can maintain an appropriate pressure in the vicinity of the nozzles of the liquid ejecting head when circulating the ink.

JP 2013-107403 A

However, in such a printer, there is a problem that the pressure control for maintaining an appropriate pressure in the vicinity of the nozzles of the liquid ejecting head becomes complicated when performing the circulation operation for circulating the ink.

A liquid ejecting apparatus that solves the above problems includes a liquid ejecting head having a nozzle surface on which nozzles for ejecting liquid are opened; a supply path, a liquid discharge path connected to a liquid outlet of the liquid ejection head to discharge the liquid from the liquid ejection head, and a pressure inside a supply-side liquid chamber provided in the liquid supply path to the nozzle. a supply-side pressure adjusting mechanism capable of adjusting a first pressure at which a gas-liquid interface formed in is maintained; and a discharge-side liquid chamber provided in the liquid discharge passage and connected to the liquid outlet, When the pressure inside the discharge-side liquid chamber is lower than the pressure outside the discharge-side liquid chamber and the first pressure, and reaches a second pressure at which the gas-liquid interface formed in the nozzle is maintained, the nozzle is opened. a discharge-side valve body that serves as a valve to connect the discharge-side liquid chamber and a fluid introduction passage through which fluid can be introduced into the discharge-side liquid chamber from outside the discharge-side liquid chamber, and is supplied to the liquid jet head; a discharge side pressure regulating valve that regulates the pressure of the liquid to a pressure that maintains the gas-liquid interface formed in the nozzle; a flow mechanism connected to the discharge-side liquid chamber by a return flow path so as to be able to discharge the liquid to the liquid discharge path side.

The perspective view of a recording device. 1 is a schematic diagram showing the configuration of a liquid ejecting apparatus; FIG. FIG. 4 is a schematic diagram showing a liquid ejecting head, a supply-side pressure regulating valve, and a maintenance device; 4-4 line arrow sectional view in FIG. FIG. 2 is a block diagram showing the electrical configuration of the liquid ejecting device; 4 is a flowchart showing an example of circulation processing; 4 is a flowchart showing an example of pressure cleaning processing; FIG. 5 is a schematic diagram showing the configuration of a liquid ejecting apparatus according to a second embodiment; FIG. 10 is a schematic diagram showing the configuration of a liquid ejecting apparatus according to a third embodiment; 10-10 line arrow sectional view in FIG. FIG. 11 is a schematic diagram showing a supply-side liquid reservoir in the fourth embodiment; FIG. 11 is a schematic diagram showing the configuration of a liquid ejecting apparatus according to a fifth embodiment;

(First embodiment)
A first embodiment of a recording apparatus including a liquid ejecting device will be described below with reference to the drawings.

As shown in FIG. 1, the recording apparatus 11 includes a liquid ejecting device 11a and has a substantially rectangular parallelepiped shape elongated in the vertical direction Z as a whole. The vertical direction Z is the direction of gravity. The liquid ejecting device 11a includes a liquid ejecting section 12 capable of ejecting ink, which is an example of liquid. The liquid ejecting unit 12 performs recording by ejecting liquid onto the paper 14 conveyed along the conveying path 13 indicated by the chain double-dashed line in the drawing. In this embodiment, the liquid ejecting section 12 is a so-called line head capable of simultaneously ejecting ink across the width direction X of the paper 14 . Note that the width direction X is a direction along the transport area in which the paper 14 is transported and a direction that intersects (for example, is perpendicular to) the transport direction Y of the paper 14 . The conveying area is a planar area along the conveying path 13 and is an area through which the paper 14 conveyed by the conveying section passes.

As shown in FIG. 2, the liquid ejecting apparatus 11a includes a liquid containing portion 15 capable of containing liquid, a plurality of liquid ejecting heads 20 for ejecting the liquid, and the liquid contained in the liquid containing portion 15 being applied to each liquid ejecting head. 20 , and a liquid discharge path 40 for discharging liquid from each liquid jet head 20 . The liquid storage unit 15 may be a liquid tank capable of injecting liquid through an injection hole (not shown) while attached to the recording apparatus 11 , or may be a liquid cartridge detachable from the recording apparatus 11 .

As shown in FIGS. 3 and 4, each liquid jet head 20 has a nozzle surface 21a in which a plurality of nozzles 21 capable of jetting liquid are opened. Each liquid jet head 20 includes a first common liquid chamber 22 to which liquid is supplied. A liquid inlet 22 a connected to the liquid supply path 30 is opened in the first common liquid chamber 22 . That is, the liquid supply path 30 is connected to the liquid inlet 22 a of each liquid jet head 20 to supply the liquid to each liquid jet head 20 .

Each liquid ejecting head 20 includes a plurality of ejecting liquid chambers 23 communicating with the first common liquid chamber 22 via the first communication passages 22b shown in FIG. A plurality of nozzles 21 are provided corresponding to a plurality of injection liquid chambers 23 . Each injection liquid chamber 23 communicates with the first common liquid chamber 22 and the nozzle 21 . A part of the wall surface of each injection liquid chamber 23 is formed by a diaphragm 24 .

Each liquid ejecting head 20 includes a plurality of actuators 25 corresponding to the plurality of ejecting liquid chambers 23 . Each actuator 25 is provided on the surface of the vibration plate 24 opposite to the portion facing each injection liquid chamber 23 . Each actuator 25 is housed in a housing chamber 26 arranged at a position different from that of the first common liquid chamber 22 . Each liquid ejecting head 20 ejects the liquid in each ejection liquid chamber 23 from each nozzle 21 as droplets by driving each actuator 25 .

As an example, each actuator 25 of the present embodiment may be composed of a piezoelectric element that contracts when a drive voltage is applied. In this case, after the vibration plate 24 is deformed with the contraction of each actuator 25 due to the application of the drive voltage, when the application of the drive voltage to each actuator 25 is released, the volume of the liquid in each injection liquid chamber 23 changes. is discharged from each nozzle 21 as droplets.

Each liquid ejecting head 20 has a second common liquid chamber 27 that communicates with each ejecting liquid chamber 23 via a second communication passage 27b shown in FIG. A liquid outflow port 27 a connected to the liquid discharge path 40 opens in the second common liquid chamber 27 . That is, the liquid discharge path 40 is connected to the liquid outlet port 27 a of each liquid jet head 20 to discharge the liquid from each liquid jet head 20 .

As shown in FIG. 2, the liquid ejecting apparatus 11a includes a return channel 50 that connects the liquid discharge channel 40 and the liquid containing portion 15, and a first on-off valve that closes the return channel 50 when closed. 51, and a fluid pump 52 as an example of a fluid mechanism for fluidizing the liquid. The flow pump 52 is provided closer to the liquid storage section 15 than the first on-off valve 51 in the return flow path 50 .

The liquid supply path 30 is provided with a degassing section 60 capable of degassing the liquid in the liquid supply path 30 . The degassing unit 60 may include, for example, a cylindrical hollow fiber membrane 61 that forms part of the liquid supply channel 30, and a decompression mechanism 62 that decompresses the liquid in the liquid supply channel 30 for degassing. can. In this case, the decompression mechanism 62 includes a decompression chamber 63 that accommodates the hollow fiber membranes 61 , a gas flow path 64 connected to the decompression chamber, and a vacuum pump 65 that decompresses the decompression chamber 63 . When the vacuum pump 65 decompresses the decompression chamber 63 , the space outside the hollow fiber membranes 61 is decompressed, and the gas dissolved in the liquid inside the hollow fiber membranes 61 is sucked to the outside of the hollow fiber membranes 61 . Thereby, the liquid inside the hollow fiber membrane 61 is degassed.

Between the degassing section 60 and each liquid ejecting head 20 in the liquid supply path 30 , a plurality of supply side pressure regulators, which are examples of a supply side pressure adjusting mechanism for adjusting the pressure of the liquid supplied to each liquid ejecting head 20 . A regulating valve 31 is provided.

As shown in FIG. 3, each supply-side pressure regulating valve 31 includes a supply-side liquid chamber 33 whose volume is changed by bending a supply-side flexible portion 32 that constitutes a wall portion, and a supply-side liquid chamber 33 . A supply side communication chamber 34 communicating with each other, a supply side valve body 35 capable of shutting off the supply side liquid chamber 33 and the supply side communication chamber 34, and a supply side urging force that biases the supply side valve body 35 in the valve closing direction. a member 36; The supply-side liquid chamber 33 of each supply-side pressure regulating valve 31 can communicate with the degassing section 60 through the liquid supply passage 30 . The supply side communication chamber 34 of each supply side pressure regulating valve 31 communicates with the first common liquid chamber 22 of each liquid jet head 20 through the liquid supply path 30 .

It should be noted that portions of the supply-side pressure regulating valve 31 such as the supply-side liquid chamber 33 and the supply-side communication chamber 34 where the cross-sectional area of the flow path is enlarged and portions such as the supply-side urging member 36 which have a complicated shape Foreign matter such as air bubbles tend to accumulate in such areas. Therefore, in this embodiment, filters 37a and 37b are provided at the inlet of each supply side pressure regulating valve 31 and inside each supply side pressure regulating valve 31 in order to trap foreign matter such as air bubbles. The number and arrangement of these filters 37a and 37b can be changed arbitrarily, and the installation of the filters 37a and 37b can be omitted.

As shown in FIG. 2, a discharge-side pressure regulating valve 41 for adjusting the pressure of the liquid supplied to the liquid jet head 20 is provided at a position where the liquid discharge path 40 and the return flow path 50 are connected. . The discharge-side pressure regulating valve 41 has a discharge-side liquid chamber 43 whose volume is changed by bending a discharge-side flexible portion 42 forming a wall portion, and a discharge-side liquid chamber 43 and a first communication hole 43a. It has a communicating first discharge side communication chamber 44 and a second discharge side communication chamber 45 communicating with the first discharge side communication chamber 44 . Further, the discharge side pressure regulating valve 41 includes a discharge side valve body 46 capable of blocking the discharge side liquid chamber 43 and the first discharge side communication chamber 44, and a discharge side valve body 46 biasing the discharge side valve body 46 in the valve closing direction. and a side biasing member 47 .

The discharge-side liquid chamber 43 communicates with the liquid discharge path 40 via the second communication hole 43b. That is, the discharge-side liquid chamber 43 is connected to the liquid outlet 27a through the liquid discharge passage 40. As shown in FIG. In other words, the liquid discharge path 40 connects the discharge side liquid chamber 43 and the liquid outlet 27 a of the second common liquid chamber 27 . Also, the discharge-side liquid chamber 43 communicates with the return channel 50 via the third communication hole 43c. In other words, the return channel 50 connects the discharge-side liquid chamber 43 and the flow pump 52 . That is, the flow pump 52 can discharge the liquid in each liquid jet head 20 to the liquid discharge path 40 side through the discharge side liquid chamber 43 . Also, the discharge-side liquid chamber 43 can communicate with the liquid storage section 15 through the return channel 50 .

The liquid injection device 11 a has a fluid introduction path 70 that communicates with the second discharge side communication chamber 45 to introduce fluid into the second discharge side communication chamber 45 . The fluid introduction path 70 is connected via a first switching valve 71 to an atmosphere communication path 72 through which air, which is an example of gas, can be introduced. Also, the fluid introduction path 70 is connected via a first switching valve 71 to a bypass flow path 73 through which the liquid can be introduced from the liquid supply path 30 . The first switching valve 71 is configured to be able to switch between a state in which the fluid introduction passage 70 and the atmosphere communication passage 72 communicate with each other and a state in which the fluid introduction passage 70 and the bypass passage 73 communicate with each other. The first switching valve 71 is, for example, a three-way valve provided with three valve bodies capable of individually closing the three flow paths of the fluid introduction path 70, the atmosphere communication path 72, and the bypass flow path 73. be able to.

One end of the atmosphere communication passage 72 communicates with the fluid introduction passage 70 and the other end is open to the atmosphere, so that the atmosphere can be introduced into the second discharge side communication chamber 45 via the fluid introduction passage 70 . It is In other words, the fluid introduction path 70 is configured to be able to introduce air into the discharge side liquid chamber 43 via the second discharge side communication chamber 45 and the first discharge side communication chamber 44 . The bypass channel 73 has one end communicating with the fluid introduction channel 70 and the other end connected between the degassing section 60 and the supply-side pressure regulating valve 31 in the liquid supply channel 30 . The liquid can be introduced into the second discharge side communication chamber 45 via the . That is, the fluid introduction path 70 is connected to the discharge side liquid chamber 43 via the second discharge side communication chamber 45 and the first discharge side communication chamber 44 , and is connected to the liquid supply path 30 via the bypass flow path 73 . It is connected to the upstream side liquid supply passage 30 a that is upstream of the supply side liquid chamber 33 . In other words, the fluid introduction path 70 is configured to allow introduction of liquid into the discharge-side liquid chamber 43 by connecting the discharge-side liquid chamber 43 and the upstream liquid supply path 30a.

The liquid ejecting apparatus 11a has a liquid flow path extending from the degassing section 60 to the first common liquid chamber 22 of each liquid ejecting head 20 at the connecting portion between the bypass flow path 73 and the upstream liquid supply path 30a. A second switching valve 74 that can switch between the supply channel 30a and the bypass channel 73 is preferably provided. As an example, the second switching valve 74 connects the upstream side of the connecting portion between the bypass flow path 73 and the bypass flow path 73 in the upstream liquid supply path 30a and the bypass flow path 73 in the upstream liquid supply path 30a. A three-way valve can be provided with three valve bodies capable of individually closing three flow paths downstream from the portion. It should be noted that the liquid ejecting device 11 a may include only one of the atmospheric communication passage 72 and the bypass passage 73 . That is, the fluid introduction path 70 may communicate with either one of the air communication path 72 and the bypass flow path 73 .

In the discharge-side liquid chamber 43, the second communication hole 43b opens downward in the vertical direction Z than the first communication hole 43a. In other words, the liquid discharge path 40 opens into the discharge side liquid chamber 43 at a position below the position where the fluid flowing from the fluid introduction path 70 flows into the discharge side liquid chamber 43 .

Further, in the discharge-side liquid chamber 43, the third communication hole 43c opens upward in the vertical direction Z than the first communication hole 43a. In other words, the return channel 50 opens into the discharge-side liquid chamber 43 at a position above the position where the fluid flowing from the fluid introduction channel 70 flows into the discharge-side liquid chamber 43 .

A temporary reservoir 80 for temporarily storing the liquid deaerated by the deaerator 60 is preferably provided between the deaerator 60 and the second switching valve 74 in the liquid supply path 30 . In addition, a pressure pump 81 is provided between the degassing part 60 and the liquid storage part 15 in the liquid supply path 30 to supply the liquid under pressure from the degassing part 60 toward each liquid jet head 20 . is preferred.

The pressurizing pump 81 can function as a liquid flow section that causes the liquid in the liquid supply path 30 to flow. That is, since the liquid in the liquid supply passage 30 is depressurized in the degassing section 60, the degassed liquid is pressurized by the pressurizing pump 81 and stored in the temporary storage section 80. Liquid can be efficiently supplied toward the ejection head 20 .

Between the degassing section 60 and the temporary storage section 80 in the liquid supply path 30, while the liquid is permitted to flow from the degassing section 60 to the temporary storage section 80, the flow from the temporary storage section 80 to the degassing section A one-way valve 82 is preferably provided to regulate the flow of liquid to 60 . This is because the reverse flow of the liquid from the temporary storage section 80, which is brought into a positive pressure state by pressurization, to the degassing section 60, which is brought into a negative pressure state by decompression, is suppressed.

A flexible storage bag is adopted as the temporary storage section 80, and the temporary storage section 80 made of such a storage bag is stored in the pressure chamber 83, and the vacuum pump 65 is pulled for pressure reduction. A configuration may be adopted in which gas is introduced into the pressurization chamber 83 through the gas flow path 64 . In this case, by driving the vacuum pump 65 to introduce gas into the pressure chamber 83, the liquid inside can be pressurized through the storage bag.

In the case of adopting this configuration, if the first three-way valve 84 is arranged on the upstream side of the vacuum pump 65 in the gas flow path 64 and the second three-way valve 85 is arranged on the downstream side, the decompression chamber 63 and the timing of pressurizing the pressure chamber 83 can be arbitrarily set.

That is, when the decompression of the decompression chamber 63 and the pressurization of the pressurization chamber 83 are performed simultaneously, the first three-way valve 84 is communicated with the outside and the second three-way valve 85 is communicated with the outside. By closing the second valve 85 a and driving the vacuum pump 65 , the gas in the decompression chamber 63 may be introduced into the pressurization chamber 83 . When the decompression chamber 63 is decompressed independently, the first valve 84a is closed and the second valve 85a is opened to drive the vacuum pump 65, thereby removing the gas drawn from the decompression chamber 63. It should be discharged to the outside. When pressurizing the pressurizing chamber 83 alone, the first valve 84a is opened, the second valve 85a is closed, and the vacuum pump 65 is driven, thereby causing the external gas to flow. It may be taken into the passage 64 and introduced into the pressure chamber 83 .

Between the degassing section 60 and the liquid supply path 30 in the liquid supply path 30, there is provided a foreign matter capturing section for capturing foreign matter such as air bubbles and dust mixed in the liquid and solidified substances of solute components dissolved in the liquid. is preferred. The contaminant capturing section may be, for example, a filter 86 for filtering the liquid, or an air trap 87 for capturing air bubbles mixed in the liquid. These may be used in combination.

In addition, when the air trap 87 has a gas-liquid separation portion 87a capable of separating gas and liquid, a discharge pump 88 for causing the liquid to flow from the liquid supply path 30 toward the gas-liquid separation portion 87a and a closing valve A second open/close valve 89 that closes the liquid supply path 30 on the side of the liquid containing portion 15 from the discharge pump 88 by entering the state is preferably provided.

The liquid ejecting apparatus 11 a includes a head holder 90 that holds each liquid ejecting head 20 . The head holder 90 holds each liquid jet head 20 in a state in which the nozzle surface 21a of each liquid jet head 20 faces downward in the vertical direction Z and is exposed. The head holder 90 also holds the supply side pressure regulating valves 31 and the discharge side pressure regulating valves 41 . The head holder 90 is configured to be displaceable along the vertical direction Z by being driven by a drive section (not shown). Each liquid jet head 20 , each supply side pressure regulating valve 31 , and each discharge side pressure regulating valve 41 do not move relative to the head holder 90 . That is, each liquid jet head 20 , each supply-side pressure regulating valve 31 , and each discharge-side pressure regulating valve 41 move as the head holder 90 moves. Further, each liquid jet head 20, each supply-side pressure regulating valve 31, and each discharge-side pressure regulating valve 41 are held by the head holder 90 so as not to move relative to each other.

As shown in FIG. 3 , the liquid ejecting apparatus 11 a includes a maintenance device 100 for performing maintenance on each liquid ejecting head 20 . The maintenance device 100 includes a cap 101 forming a closed space in which the nozzles 21 provided in each liquid jet head 20 are opened, a suction mechanism 102 , and a wiper unit 103 .

The cap 101 is configured to be able to form a closed space by contacting the nozzle surface 21 a of each liquid jet head 20 . In the following description, capping means that the cap 101 contacts the nozzle surface 21a of each liquid jet head 20 to form a closed space. Note that capping can be performed by moving each liquid jet head 20 toward the cap 101 or by moving the cap 101 toward each liquid jet head 20 . Further, the object that the cap 101 comes into contact with during capping is not limited to the nozzle surface 21a. A closed space with an opening 21 can also be formed. The cap 101 is provided with a cap open valve 101a for opening the closed space to the atmosphere.

The suction mechanism 102 includes a waste liquid tank 102a, a waste liquid channel 102b connecting the waste liquid tank 102a and the cap 101, and a decompression pump 102c arranged in the middle of the waste liquid channel 102b. The wiper unit 103 includes a wiper 103a that wipes the nozzle surface 21a, and a moving body 103b that holds and moves the wiper 103a.

Further, as shown in FIG. 5, the liquid ejecting apparatus 11a includes a control section 200 that controls the constituent elements of the liquid ejecting apparatus 11a. The control unit 200 controls each liquid jet head 20, the fluid pump 52, the vacuum pump 65, the pressure pump 81, the discharge pump 88, and the decompression pump 102c. The control unit 200 also controls the first on-off valve 51, the second on-off valve 89, the first switching valve 71, the second switching valve 74, the first three-way valve 84, the second three-way valve 85, the cap opening valve 101a, and control the moving body 103b. The control unit 200 can be provided with a plurality of units that individually control the constituent elements, or can be provided with a unit that comprehensively controls a plurality of constituent elements.

Under the control of the control unit 200, the liquid injection device 11a closes the first on-off valve 51 and the cap open valve 101a, and switches the flow path of the liquid to the liquid supply path 30 by the second switching valve 74. Normal state. Further, in a normal state, the control unit 200 caps each liquid ejecting head 20 with the cap 101 to suppress drying of the nozzles 21 .

When the liquid injection device 11a is started, the discharge pump 88 and the pressure pump 81 are driven and controlled by the control unit 200 so that the inside of the temporary reservoir 80 is maintained at a predetermined positive pressure (pressurized state). . As a result, in a normal state, the temporary reservoir 80, the supply-side communication chambers 34 of the supply-side pressure regulating valves 31, and the liquid supply path 30 between the temporary reservoir 80 and the supply-side communication chambers 34 are maintained at a predetermined pressure. held under pressure. In addition, the control unit 200 reduces the pressure in the pressure reduction chamber 63 by controlling the vacuum pump 65, the first three-way valve 84, and the second three-way valve 85 according to the drive of the pressure pump 81, and degassed. of liquid is sent to temporary reservoir 80 .

Even if the liquid in the supply-side communication chamber 34 of each supply-side pressure regulating valve 31 is in a pressurized state, the supply-side valve body 35 of each supply-side pressure regulating valve 31 is pushed by the urging force of the supply-side urging member 36 . Liquid does not flow from the supply communication chamber 34 to the supply liquid chamber 33 while the supply-side liquid chamber 33 and the supply-side communication chamber 34 are kept disconnected.

Here, each of the supply side pressure regulating valve 31 and the discharge side pressure regulating valve 41 of this embodiment will be described in detail.
As shown in FIG. 3 , the supply-side flexible portion 32 of each supply-side pressure regulating valve 31 receives the pressure of the liquid in the supply-side liquid chamber 33 at the supply-side inner surface 32 a that is the inner surface of the supply-side liquid chamber 33 . The supply-side flexible portion 32 receives the atmospheric pressure at the supply-side outer surface 32 b that is the outer surface of the supply-side liquid chamber 33 . Therefore, the supply-side flexible portion 32 of each supply-side pressure regulating valve 31 bends when the pressure in the supply-side liquid chamber 33 fluctuates. In one example of the present embodiment, the pressure inside the supply-side liquid chamber 33 refers to the pressure applied to the central portion of the supply-side flexible portion 32 .

The supply-side flexible portion 32 bends when the amount of liquid in the supply-side liquid chamber 33 changes, thereby displacing the center of the supply-side flexible portion 32 and changing the volume of the supply-side liquid chamber 33 . When the amount of liquid in the supply-side liquid chamber 33 decreases due to the liquid being discharged from the supply-side liquid chamber 33, the pressure in the supply-side liquid chamber 33 decreases. It bends in the direction of reducing the volume of the supply-side liquid chamber 33 . Further, when the amount of liquid in the supply-side liquid chamber 33 increases due to the liquid flowing into the supply-side liquid chamber 33, the pressure in the supply-side liquid chamber 33 rises. , in the direction of increasing the volume of the supply-side liquid chamber 33 .

In each supply-side pressure regulating valve 31 , the supply-side valve body 35 is connected to the supply-side inner surface 32 a of the supply-side flexible portion 32 . The supply-side valve body 35 of each supply-side pressure regulating valve 31 moves according to the displacement of the supply-side inner surface 32a. The supply-side valve element 35 of each supply-side pressure regulating valve 31 opens when the supply-side flexible portion 32 is displaced in the direction of decreasing the volume of the supply-side liquid chamber 33, thereby It communicates with the side communication chamber 34 . Further, the supply-side valve body 35 of each supply-side pressure regulating valve 31 closes when the supply-side flexible portion 32 is displaced in the direction of increasing the volume of the supply-side liquid chamber 33 . and the supply side communication chamber 34 are cut off.

In each of the supply-side pressure regulating valves 31, the supply-side biasing member 36 biases the supply-side valve body 35 in the direction of closing the valve. In each of the supply-side pressure regulating valves 31, the supply-side valve body 35 is set to a first pressure (for example, in FIG. 2, When the atmospheric pressure is -500 Pa to -1000 Pa), the valve is opened to allow the supply side liquid chamber 33 and the supply side communication chamber 34 to communicate with each other. The first pressure consists of the pressing force of the supply-side biasing member 36, the force required to displace the supply-side flexible portion 32, and the supply-side valve body 35 that separates the supply-side liquid chamber 33 and the supply-side communication chamber 34 from each other. It is determined according to the seal load, which is the pressing force required for shutting off, the pressure inside the supply side communication chamber 34 acting on the surface of the supply side valve body 35 , and the pressure inside the supply side liquid chamber 33 . That is, the greater the pressing force of the supply-side biasing member 36, the lower the first pressure required for changing the valve from the closed state to the open state. That is, the first pressure can be set by determining the pressing force of the supply side biasing member 36 .

The first pressure is set to the pressure in the supply-side liquid chamber 33 that can maintain the gas-liquid interface formed in the nozzle 21 of each liquid jet head 20 . In this case, the gas-liquid interface is the boundary where the liquid and the gas are in contact. A pressure capable of maintaining the gas-liquid interface formed in the nozzle 21 (for example, +500 Pa to −3500 Pa relative to atmospheric pressure) is, in other words, a pressure capable of forming a meniscus at the gas-liquid interface of the nozzle 21 . A meniscus is a curved liquid surface that the liquid forms in contact with the nozzle 21 . It is preferable that the nozzle 21 has a concave meniscus suitable for ejecting droplets. The difference between the pressure applied to the gas-liquid interface formed in the nozzle 21 and the pressure in the supply side liquid chamber 33 is determined by the distance D1 between the position of the nozzle surface 21a and the center position of the supply side flexible portion 32 in the vertical direction Z. Change. Therefore, the first pressure is set in consideration of the distance D1 (for example, 50 mm in FIG. 2) between the position of the nozzle surface 21a and the center position of the supply-side flexible portion 32 in the vertical direction Z. In the following description, the pressure applied to the gas-liquid interface formed on the nozzle 21 is referred to as the pressure applied to the nozzle 21 .

In each of the supply-side pressure regulating valves 31, when the pressure inside the supply-side liquid chamber 33 reaches the first pressure, the supply-side valve element 35 opens to allow the liquid to flow from the supply-side communication chamber 34 into the supply-side liquid chamber 33. flows in. That is, each supply-side pressure regulating valve 31 can adjust the pressure in the supply-side liquid chamber 33 to the first pressure at which the gas-liquid interface formed in the nozzle 21 is maintained. In other words, each supply-side pressure regulating valve 31 adjusts the pressure of the liquid supplied to each liquid jet head 20 to a pressure that maintains the gas-liquid interface formed in the nozzle 21 .

As shown in FIG. 2 , the discharge-side flexible portion 42 of the discharge-side pressure regulating valve 41 receives the pressure of the liquid in the discharge-side liquid chamber 43 at the discharge-side inner surface 42 a serving as the inner surface of the discharge-side liquid chamber 43 . The discharge-side flexible portion 42 receives the atmospheric pressure at a discharge-side outer surface 42 b that serves as the outer surface of the discharge-side liquid chamber 43 . Therefore, the discharge-side flexible portion 42 bends when the pressure in the discharge-side liquid chamber 43 fluctuates. In one example of the present embodiment, the pressure in the discharge side liquid chamber 43 refers to the pressure applied to the central portion of the discharge side flexible portion 42 .

The discharge-side flexible portion 42 bends when the amount of liquid in the discharge-side liquid chamber 43 changes, thereby displacing the center of the discharge-side flexible portion 42 and changing the volume of the discharge-side liquid chamber 43 . When the amount of liquid in the discharge-side liquid chamber 43 decreases as the liquid is discharged from the discharge-side liquid chamber 43, the pressure in the discharge-side liquid chamber 43 decreases. It bends in the direction to reduce the volume of the discharge side liquid chamber 43 . In addition, when the amount of liquid in the discharge-side liquid chamber 43 increases due to the liquid flowing into the discharge-side liquid chamber 43, the pressure in the discharge-side liquid chamber 43 rises. , in the direction of increasing the volume of the discharge-side liquid chamber 43 .

The discharge side valve body 46 is arranged so as to be able to contact the discharge side inner surface 42 a of the discharge side flexible portion 42 . The discharge-side valve body 46 moves in contact with the discharge-side inner surface 42a according to the displacement of the discharge-side inner surface 42a. The discharge-side valve body 46 opens when displaced in the direction of decreasing the volume of the discharge-side liquid chamber 43 to allow the discharge-side liquid chamber 43 and the first discharge-side communication chamber 44 to communicate with each other. The discharge-side valve body 46 closes when the discharge-side flexible portion 42 is displaced in the direction of increasing the volume of the discharge-side liquid chamber 43 , thereby separating the discharge-side liquid chamber 43 and the first discharge-side communication chamber 44 . Cut off.

The discharge-side biasing member 47 biases the discharge-side valve element 46 in the direction of closing the valve. The discharge-side valve body 46 is set so that the pressure inside the discharge-side liquid chamber 43 is lower than the pressure outside the discharge-side liquid chamber 43 and the first pressure (for example, in FIG. -3500 Pa), the valve is opened to allow the discharge side liquid chamber 43 and the first discharge side communication chamber 44 to communicate with each other. The second pressure is the pressing force of the discharge-side biasing member 47, the force required to displace the discharge-side flexible portion 42, and the pressure between the discharge-side liquid chamber 43 and the first discharge-side communication chamber 44 by the discharge-side valve body 46. , the pressure in the first discharge side communication chamber 44 acting on the surface of the discharge side valve body 46, and the pressure in the discharge side liquid chamber 43. That is, the larger the pressing force of the discharge-side urging member 47, the lower the second pressure for changing the valve from the closed state to the open state. That is, the second pressure can be set by determining the pressing force of the ejection-side biasing member 47 .

The second pressure is the pressure in the discharge-side liquid chamber 43 capable of maintaining the gas-liquid interface formed in the nozzle 21 and is set to a pressure lower than the first pressure. The difference between the pressure applied to the nozzle 21 and the pressure in the discharge-side liquid chamber 43 varies depending on the distance D2 between the position of the nozzle surface 21a and the center position of the discharge-side flexible portion 42 in the vertical direction Z. FIG. Therefore, the second pressure is set in consideration of the distance D2 between the position of the nozzle surface 21a and the center position of the discharge side flexible portion 42 in the vertical direction Z (for example, 50 mm, which is the same as D1 in FIG. 2). .

In one example of this embodiment, the center position of the discharge side flexible portion 42 coincides with the center position of the supply side flexible portion 32 in the vertical direction Z. As shown in FIG. That is, in one example of this embodiment, the distance D1 matches the distance D2.

In the discharge-side pressure regulating valve 41, when the pressure in the discharge-side liquid chamber 43 becomes the first pressure, the discharge-side valve body 46 opens to allow the flow from the first discharge-side communication chamber 44 to the discharge-side liquid chamber 43. Liquid inflow. That is, the discharge side pressure regulating valve 41 can adjust the pressure in the discharge side liquid chamber 43 to the second pressure at which the gas-liquid interface formed in the nozzle 21 is maintained. In other words, the discharge-side pressure regulating valve 41 adjusts the pressure of the liquid supplied to each liquid jet head 20 to a pressure that maintains the gas-liquid interface formed in the nozzle 21 .

In one example of this embodiment, the discharge side flexible section 42 has a larger area than the supply side flexible section 32 . Therefore, the volume of the discharge-side liquid chamber 43 that can be changed by the discharge-side flexible portion 42 is larger than the volume of the supply-side liquid chamber 33 that can be changed by the supply-side flexible portion 32 .

Next, flow path resistance when the liquid is supplied from each supply side pressure regulating valve 31 to each liquid jet head 20 and discharged from each liquid supply head to the discharge side pressure regulating valve 41 will be described. In the following description, the direction in which liquid flows from the supply-side pressure regulating valve 31 to the discharge-side pressure regulating valve 41 via each liquid jet head 20 is referred to as the flow direction.

As shown in FIG. 4, the second flow path R2 from the nozzle 21 to the discharge-side liquid chamber 43 extends from the supply-side liquid chamber 33 of each supply-side pressure regulating valve 31 to the nozzle 21 of each liquid jet head 20. The flow path resistance is small compared to the first flow path R1 between. The flow resistance decreases when the cross-sectional area of the flow channel when cut along the plane perpendicular to the flow direction is increased, while the cross-sectional area of the flow channel when cut along the plane perpendicular to the flow direction decreases. It becomes larger when the area is made smaller. Further, the flow path resistance decreases when the length of the flow path in the flow direction is shortened, and increases when the length of the flow path in the flow direction is lengthened.

Here, Qm (m ³ /s) is the flow rate of the liquid flowing through the first flow path R1 and the second flow path R2 when the circulation operation is performed while the liquid is not being jetted from the nozzles 21 of the liquid jet head 20, P1 (Pa) as the first pressure, P2 (Pa) as the second pressure, Pn (Pa) as the pressure in the nozzle 21, Ru (Pa·s/m ³ ) as the flow path resistance of the first flow path R1, Assuming that the flow path resistance of the second flow path R2 is Rd (Pa·s/m ³ ),
P1-P2=(Ru+Rd)*Qm
Pn-P2=Rd*Qm→Pn=P2+Rd*Qm
Further, when the liquid is ejected from the nozzles 21 of the liquid ejecting head 20 and the circulation operation is performed, the flow rate of the liquid flowing through the second flow path R2 is Qj (m ³ /s), and the liquid ejected from the nozzles 21 is Qj (m 3 /s). Assuming the flow rate of U (m ³ /s),
P1-P2=Ru*(U+Qj)+Rd*Qj
Pn-P2=Rd*Qj→Pn=P2+Rd*Qj
In any case, in order to maintain the pressure of the liquid in the nozzle 21 with high accuracy, the difference between the pressure Pn of the liquid in the nozzle and the second pressure P2 should be small. It is preferable to set the path resistance Rd small.

In one example of the present embodiment, the cross-sectional area of the liquid supply channel 30 in the first channel R1 when cut along a plane orthogonal to the channel direction is the same as that of the liquid discharge channel 40 in the second channel R2 in the channel direction. smaller than the cross-sectional area when cut by a plane orthogonal to Therefore, the flow path resistance of the liquid discharge passage 40 from each liquid jet head 20 to the discharge side pressure regulating valve 41 is equal to that of the liquid supply passage 30 from the supply side pressure regulating valve 31 to each liquid jet head 20. smaller than the flow path resistance.

In one example of the present embodiment, the cross-sectional area of the second common liquid chamber 27 in the second flow path R2 when cut along a plane orthogonal to the flow direction is the first common liquid in the first flow path R1. It is larger than the cross-sectional area of the chamber 22 taken along a plane perpendicular to the direction of the flow path. Therefore, the flow path resistance between the second communication path 27b and the liquid outlet 27a in the second common liquid chamber 27 is equal to that between the liquid inlet 22a and the first communication path 22b in the first common liquid chamber 22. smaller than the flow path resistance.

On the other hand, in one example of the present embodiment, the length of the second communication path 27b in the flow direction in the second flow path R2 is equal to the flow direction of the first communication path 22b in the first flow path R1. longer than the channel length in Therefore, the flow path resistance of the second communication path 27b is greater than the flow path resistance of the first communication path 22b.

In one example of the present embodiment, the first communication path 22b and the second communication path 27b are arranged so that the flow path resistance in the second flow path R2 is smaller than the flow path resistance in the first flow path R1. 22b is configured to be smaller than the flow path resistance of the second communication path 27b. In addition, in order to configure in this way, for the first flow path R1 and the second flow path R2, the flow path resistance in the liquid supply path 30 and the first common liquid chamber 22 in the first flow path R1 and the second flow resistance The difference between the flow path resistance in the liquid discharge path 40 and the second common liquid chamber 27 in the path R2 is larger than the difference between the flow path resistance in the first communication path 22b and the second communication path 27b. should be configured to

Next, maintenance operations for maintaining the liquid ejection device 11a and various processes executed by the control unit 200 will be described.
The liquid ejecting device 11a can execute a circulation operation for circulating the liquid in the liquid ejecting device 11a as a maintenance operation. In the liquid ejecting device 11a, when the flow of the liquid is stagnant, the liquid tends to thicken or bubbles tend to accumulate. In this case, the nozzles 21 and the ejection liquid chambers 23 are not in a normal state, so that the nozzles 21 are likely to cause liquid ejection failure. Therefore, the liquid ejecting device 11a is configured to perform a circulation operation for circulating the liquid in the liquid ejecting device 11a. A circulation process for performing a circulation operation will be described below.

As shown in FIG. 6, the controller 200 opens the first on-off valve 51 to allow the flow pump 52 and the discharge-side liquid chamber 43 to communicate with each other in step S11. Subsequently, in step S12, the controller 200 drives the flow pump 52 to discharge the liquid in the discharge-side liquid chamber 43 to the return channel 50 side. That is, the controller 200 starts reducing the pressure in the discharge-side liquid chamber 43 in step S12. Thereby, the control unit 200 circulates the liquid in the liquid ejecting device 11a. The flow of the liquid when the liquid in the liquid ejecting device 11a circulates will be described later in detail.

Subsequently, the controller 200 stops driving the fluid pump 52 in step S13. That is, the control section 200 stops depressurization of the discharge side liquid chamber 43 in step S13. After that, in step S14, the control unit 200 closes the first opening/closing valve 51 and terminates the circulation process.

Here, the flow of liquid in the circulation operation will be described.
As shown in FIG. 2, when the pressure in the discharge side liquid chamber 43 is higher than the second pressure, the discharge side valve body 46 does not open, and the discharge side liquid chamber 43 and the first discharge side communication chamber are closed. 44 are blocked. Therefore, when the discharge side liquid chamber 43 is depressurized, liquid flows into the discharge side liquid chamber 43 from the second common liquid chamber 27 of each liquid jet head 20 via the liquid discharge path 40 . In each liquid ejecting head 20, when the liquid flows from the second common liquid chamber 27 into the discharge side liquid chamber 43, the pressure in the second common liquid chamber 27 decreases, so that the ejecting liquid chamber is discharged via the second communication passage 27b. Liquid flows into the second common liquid chamber 27 from 23 . In each liquid ejecting head 20, when the liquid flows from the ejecting liquid chamber 23 into the second common liquid chamber 27, the pressure inside the ejecting liquid chamber 23 decreases. In one example of this embodiment, the second pressure is set to a pressure that can maintain a meniscus at the air-liquid interface of the nozzle 21 . Therefore, when the pressure in the ejection-side liquid chamber 43 is higher than the second pressure, the meniscus is maintained at the air-liquid interface of the nozzle 21 when the pressure in the ejection liquid chamber 23 of each liquid ejection head 20 decreases. In this state, liquid flows from the first common liquid chamber 22 into the injection liquid chamber 23 . That is, when the pressure in the discharge side liquid chamber 43 is higher than the second pressure, when the pressure in the ejection liquid chamber 23 of each liquid ejection head 20 decreases, air is not drawn in from the nozzles 21 and the first common Liquid flows in from the liquid chamber 22 . In each liquid ejecting head 20, when the liquid in the first common liquid chamber 22 flows into the ejecting liquid chamber 23, the pressure in the first common liquid chamber 22 decreases. Liquid flows into the first common liquid chamber 22 from the supply side liquid chamber 33 of the valve 31 .

As the liquid flows from the supply-side liquid chamber 33 of each supply-side pressure regulating valve 31 into the first common liquid chamber 22 of each liquid jet head 20, the pressure in the supply-side liquid chamber 33 decreases to the first pressure. Then, the supply-side valve body 35 is opened, and the supply-side liquid chamber 33 and the supply-side communication chamber 34 are communicated with each other. In one example of this embodiment, the supply-side communication chamber 34 of each supply-side pressure regulating valve 31 is held in a pressurized state. Therefore, when the supply-side valve element 35 is opened in each supply-side pressure regulating valve 31 and the supply-side liquid chamber 33 and the supply-side communication chamber 34 are communicated with each other, the supply-side liquid is discharged from the supply-side communication chamber 34 . Liquid flows into chamber 33 . As a result, the pressure in the supply-side liquid chamber 33 of each supply-side pressure regulating valve 31 rises and is adjusted to the first pressure.

In one example of the present embodiment, the first pressure is set to the pressure of the supply-side liquid chamber 33 that can maintain the meniscus at the gas-liquid interface of the nozzles 21 of each liquid jet head 20 . Therefore, in the liquid ejecting apparatus 11a, the pressure in the supply-side liquid chamber 33 of each supply-side pressure regulating valve 31 is adjusted to the first pressure, so that the gas-liquid interface of the nozzle 21 of each liquid ejecting head 20 A meniscus can be maintained.

On the other hand, in one example of the present embodiment, the second pressure is the pressure in the discharge side liquid chamber 43 capable of maintaining the meniscus at the gas-liquid interface of the nozzles 21 of each liquid jet head 20, and the first pressure. set to a lower pressure than Therefore, when the liquid in the discharge side liquid chamber 43 is discharged to the return channel 50 side in the circulation process, in principle, the pressure in the discharge side liquid chamber 43 decreases to the second pressure and the discharge side valve body 46 is opened, the pressure in the supply-side liquid chamber 33 of each supply-side pressure regulating valve 31 is lowered to the first pressure, and the supply-side valve body 35 is opened. According to this, in the liquid injection device 11a, before the pressure in the discharge-side liquid chamber 43 reaches the second pressure, the supply-side communication chamber 34 of each supply-side pressure regulating valve 31 reaches the supply-side liquid chamber 33 and the liquid is discharged. Liquid can be supplied to the ejection liquid chamber 23 via the supply path 30 and the first common liquid chamber 22 . Therefore, in the liquid ejecting apparatus 11 a , the pressure inside the ejecting liquid chamber 23 of each liquid ejecting head 20 can be adjusted to a pressure that can maintain the meniscus at the air-liquid interface of the nozzle 21 .

However, depending on the discharge amount of the liquid when the flow pump 52 is driven to discharge the liquid from the discharge side liquid chamber 43 to the return channel 50 side, the pressure in the discharge side liquid chamber 43 temporarily rises to the second pressure. It can also be assumed that As an example, when the liquid is discharged from the discharge-side liquid chamber 43 to the return channel 50 side, the discharge amount of the liquid from the supply-side communication chamber 34 of each supply-side pressure regulating valve 31 to the supply-side liquid chamber 33 is If the supply amount is exceeded, the pressure in the discharge side liquid chamber 43 may reach the second pressure.

In this case, the discharge side valve body 46 is opened, and the discharge side liquid chamber 43 and the first discharge side communication chamber 44 are communicated with each other. Therefore, the fluid introduced from the fluid introduction passage 70 into the second discharge side communication chamber 45 flows into the discharge side liquid chamber 43 via the first discharge side communication chamber 44 . As a result, the pressure in the discharge side liquid chamber 43 rises and is adjusted to the second pressure. Therefore, in the liquid injection device 11a, the meniscus can be maintained at the air-liquid interface of the nozzle 21 by adjusting the pressure in the discharge side liquid chamber 43 to the second pressure.

When the fluid is caused to flow from the fluid introduction path 70 into the discharge side liquid chamber 43 via the second discharge side communication chamber 45 and the first discharge side communication chamber 44, the control unit 200 switches the first switching valve 71 to the fluid introduction path. The air can flow into the discharge side liquid chamber 43 by switching to a state in which the air communication passage 72 communicates with the air communication passage 70 . Further, when the fluid is caused to flow into the discharge side liquid chamber 43 from the fluid introduction passage 70 via the second discharge side communication chamber 45 and the first discharge side communication chamber 44, the control section 200 switches the first switching valve 71 to the fluid state. By switching the introduction channel 70 and the bypass channel 73 to communicate with each other, the liquid can flow from the temporary reservoir 80 into the discharge-side liquid chamber 43 .

As described above, in the circulation operation, the liquid in the liquid ejecting device 11a circulates while maintaining the meniscus at the gas-liquid interface of the nozzle 21 .
Further, the liquid ejecting device 11a may be configured to perform wiping to wipe the nozzle surface 21a with the wiper 103a as a maintenance operation. Wiping can be performed to remove foreign matter such as liquid and dust adhering to the nozzle surface 21a. The controller 200 can perform wiping by moving the moving body 103b along the nozzle surface 21a while the tip of the wiper 103a is in contact with the nozzle surface 21a. Note that wiping can also be performed by moving each liquid jet head 20 while in contact with the wiper 103a.

Further, the liquid ejecting apparatus 11a may be configured to eject the liquid from the nozzles 21 of the liquid ejecting heads 20 toward the cap 101 as a maintenance operation, thereby performing flushing for discharging the liquid in the nozzles 21. good. Flushing may be performed to prevent or clear clogging of nozzles 21, such as between prints, or may be performed to straighten the meniscus of liquid formed in nozzles 21, such as after wiping. can.

Further, the liquid ejecting apparatus 11 a may be configured to perform a cleaning operation of discharging the liquid from the ejection liquid chamber 23 through the nozzle 21 as a maintenance operation. Since the cleaning operation discharges a larger amount of liquid from the nozzles 21 than the flushing operation, it can be said that the cleaning operation is more effective in eliminating the clogging of the nozzles 21 than the flushing operation.

The liquid ejecting device 11a may be configured to perform suction cleaning as the cleaning operation. The control unit 200 can perform suction cleaning by driving the decompression pump 102c to reduce the pressure in the closed space and discharge the liquid from the nozzle 21 in the capped state.

Further, the liquid ejecting device 11a may be configured to perform pressure cleaning as the cleaning operation. A pressure cleaning process for performing pressure cleaning will be described below.

As shown in FIG. 7, the control unit 200 releases the capping of each liquid jet head 20 in step S21. Incidentally, when the capping is released, the cap 101 is arranged at a position facing the opening of the nozzle surface 21a.

Next, in step S22, the controller 200 opens the first on-off valve 51 to allow the flow pump 52 and the discharge-side liquid chamber 43 to communicate with each other. Subsequently, in step S23, the controller 200 drives the flow pump 52 to start pressurizing the discharge side liquid chamber 43. As shown in FIG. When the pressure in the discharge side liquid chamber 43 increases, the discharge side valve body 46 closes to block the discharge side liquid chamber 43 and the first discharge side communication chamber 44 . Therefore, when the pressure in the discharge-side liquid chamber 43 increases, the liquid stored in the discharge-side liquid chamber 43 is pressurized and supplied to the second common liquid chamber 27 of each liquid jet head 20 through the liquid discharge path 40 . Then, the liquid in the second common liquid chamber 27 flows into the injection liquid chamber 23 and out of the nozzle 21 and is received by the cap 101 . As a result, foreign substances that cause poor ejection, such as air bubbles in the second common liquid chamber 27 and the ejection liquid chamber 23 and liquid thickened by evaporation of the solvent component, are discharged through the nozzle 21 together with the liquid.

When a sufficient amount of liquid is discharged from the nozzle 21 to discharge the foreign matter, the controller 200 stops driving the flow pump 52 to stop pressurizing the discharge side liquid chamber 43 in step S24. Further, the control unit 200 closes the first on-off valve 51 to shut off the flow pump 52 and the discharge side liquid chamber 43 as step S25.

Next, in step S26, the control unit 200 starts driving the decompression pump 102c. As a result, the liquid accumulated in the cap 101 is discharged to the waste liquid tank 102a through the waste liquid channel 102b. After the liquid in the cap 101 has been discharged, the controller 200 stops driving the decompression pump 102c in step S27.

After that, in step S28, the control unit 200 moves the moving body 103b to perform wiping. As a result, droplets and the like adhering to the nozzle surface 21a as the liquid is discharged from the nozzle 21 are removed.

Then, in step S29, the control unit 200 performs flushing to adjust the meniscus of the nozzle 21, and in step S30, performs capping, thereby completing the pressure cleaning process. Note that the capping in step S30 may not be performed when printing is to be performed immediately after the execution of the pressure cleaning.

Next, the operation of the liquid injection device 11a of this embodiment will be described.
When the circulation operation for circulating the liquid in the liquid injection device 11a is performed, the discharge side pressure regulating valve 41 causes the discharge side flexible portion 42 to bend when the pressure in the discharge side liquid chamber 43 reaches the second pressure. As a result, the discharge side valve body 46 is opened to allow the fluid to flow into the discharge side liquid chamber 43 from the fluid introduction passage 70 . Therefore, in the discharge side pressure regulating valve 41, the pressure in the discharge side liquid chamber 43 can form a meniscus at the air-liquid interface of the nozzle 21 even when the liquid is discharged to the return channel 50 side in the circulation operation. is adjusted to a second pressure.

When the supply-side pressure regulating valve 31 performs the circulation operation, the supply-side flexible portion 32 is flexed when the pressure in the supply-side liquid chamber 33 reaches the first pressure. is opened to allow liquid to flow from the supply side communication chamber 34 into the supply side liquid chamber 33 . Therefore, in the supply-side pressure regulating valve 31, the pressure in the supply-side liquid chamber 33 can form a meniscus at the air-liquid interface of the nozzle 21 even when the liquid is discharged to the return channel 50 side in the circulation operation. is adjusted to a first pressure.

The liquid discharge path 40 communicates with the discharge side liquid chamber 43 at a second communication hole 43b positioned below in the vertical direction Z than the first communication hole 43a through which the fluid flowing from the fluid introduction path 70 flows into the discharge side liquid chamber 43. Connecting. Therefore, the liquid ejecting device 11a can suppress the fluid that has flowed in from the fluid introduction path 70 from flowing toward the second communication hole 43b.

The return flow path 50 communicates with the discharge side liquid chamber 43 at a third communication hole 43c positioned above the first communication hole 43a through which the fluid flowing from the fluid introduction path 70 flows into the discharge side liquid chamber 43 in the vertical direction Z. Connecting. Therefore, the liquid ejecting device 11a can guide the fluid that has flowed from the fluid introduction path 70 toward the third communication hole 43c.

The fluid introduction path 70 can communicate with a bypass flow path 73 that connects with an upstream liquid supply path 30 a that is upstream of the supply side liquid chamber 33 in the liquid supply path 30 . Therefore, in the liquid ejecting apparatus 11 a , the same liquid as the liquid supplied to each liquid ejecting head 20 from the liquid supply path 30 can flow from the fluid introduction path 70 into the discharge side liquid chamber 43 .

The fluid introduction path 70 is connectable with an atmosphere communication path 72 . Therefore, in the liquid ejecting device 11a, the air can flow into the discharge side liquid chamber 43 from the fluid introduction passage 70. As shown in FIG.
The difference between the pressure in the discharge-side liquid chamber 43 and the pressure applied to the nozzle 21 during the circulation operation increases as the flow path resistance from the discharge-side liquid chamber 43 to the nozzle 21 increases. In one example of this embodiment, the flow path resistance of the second flow path R2 between the nozzle 21 and the discharge side liquid chamber 43 is the flow path resistance of the first flow path R1 between the supply side liquid chamber 33 and the nozzle 21. less than resistance. Therefore, the difference between the pressure in the discharge side liquid chamber 43 and the pressure applied to the nozzle 21 can be reduced.

The flow resistance of the second communication path 27b is greater than the flow resistance of the first communication path 22b. Therefore, when the liquid is ejected from the nozzle 21 , the liquid can easily flow from the first common liquid chamber 22 to the jetting liquid chamber 23 , and the liquid can flow from the second common liquid chamber 27 into the jetting liquid chamber 23 . can be suppressed.

In the discharge side pressure regulating valve 41, when the liquid is discharged from the discharge side liquid chamber 43 toward the return passage 50 side, the discharge side flexible portion 42 bends, so that the volume of the discharge side liquid chamber 43 is reduced. Therefore, when the liquid is discharged from the discharge-side liquid chamber 43 to the return channel 50 side, the discharge-side pressure regulating valve 41 is connected to the discharge-side liquid chamber 43 via the liquid discharge channel 40 . The amount of liquid drawn from the second common liquid chamber 27 of 20 can be reduced. That is, the discharge-side pressure regulating valve 41 reduces pressure fluctuations that occur inside each liquid jet head 20 when the liquid is discharged from the discharge-side liquid chamber 43 to the return flow path 50 side. Furthermore, the volume of the discharge side liquid chamber 43 in which the discharge side flexible portion 42 can be changed is larger than the volume of the supply side liquid chamber 33 in which the supply side flexible portion 32 can be changed. Therefore, the discharge-side pressure regulating valve 41 can suitably reduce pressure fluctuations even when a large amount of liquid is discharged from the discharge-side liquid chamber 43 to the return channel 50 side.

Each liquid jet head 20, each supply side pressure regulating valve 31, and each discharge side pressure regulating valve 41 are held by the head holder 90 in a state in which they do not move relative to each other. Therefore, the distance in the vertical direction Z between the nozzle surface 21a and each of the supply-side pressure regulating valves 31 does not change even when the head holder 90 is displaced along the vertical direction Z. Therefore, in one example of the present embodiment, it is possible to suppress a change in the pressure applied to the nozzle 21 due to a change in the distance in the vertical direction Z between the nozzle surface 21a and each of the supply-side pressure regulating valves 31 .

Further, the distance in the vertical direction Z between the nozzle surface 21a and the discharge side pressure regulating valve 41 does not change even if the head holder 90 is displaced along the vertical direction Z. Therefore, in one example of the present embodiment, it is possible to suppress a change in the pressure applied to the nozzle 21 due to a change in the distance in the vertical direction Z between the nozzle surface 21 a and the discharge side pressure regulating valve 41 .

Effects of the present embodiment will be described.
(1) The liquid ejecting apparatus 11 a has a discharge side pressure regulating valve 41 in the liquid discharge path 40 for discharging the liquid from each liquid jet head 20 . Therefore, the liquid ejecting apparatus 11a can reduce pressure fluctuations in the nozzle 21 when discharging the liquid from the liquid outlet 27a by driving the flow pump 52 in the circulation operation for circulating the liquid. Therefore, the liquid ejecting device 11a can prevent the pressure control from becoming complicated when performing the circulation operation.

(2) The liquid injection device 11 a can adjust the pressure of the supply side liquid chamber 33 by the supply side pressure adjustment valve 31 . Therefore, the liquid ejecting apparatus 11a can easily control the pressure of the supply-side liquid chamber 33 compared to the case where the pressure of the supply-side liquid chamber 33 is adjusted using, for example, a pump and a sensor.

(3) Since the liquid injection device 11a can reduce the pressure fluctuation in the supply-side liquid chamber 33 by bending the supply-side flexible portion 32, the pressure control of the supply-side liquid chamber 33 can be facilitated.
(4) Since the liquid ejecting device 11a can reduce pressure fluctuations in the discharge-side liquid chamber 43 by bending the discharge-side flexible portion 42, pressure control of the discharge-side liquid chamber 43 can be facilitated.

(5) The liquid ejecting device 11a can prevent the fluid that has flowed into the discharge-side liquid chamber 43 from the fluid introduction path 70 from flowing into the liquid discharge path 40 side.
(6) The liquid ejection device 11 a can efficiently discharge the fluid that has flowed into the discharge side liquid chamber 43 from the fluid introduction path 70 from the discharge side liquid chamber 43 via the return flow path 50 .

(7) When the pressure in the discharge-side liquid chamber 43 reaches the second pressure, the liquid ejecting apparatus 11a introduces the same liquid as the liquid supplied to each liquid ejecting head 20 into the discharge-side liquid chamber 43, thereby The pressure in the liquid chamber 43 can be maintained.

(8) In the liquid injection device 11a, the pressure in the discharge side liquid chamber 43 is set to be lower than the second pressure in a state where the first switching valve 71 is switched to the state in which the fluid introduction passage 70 and the atmosphere communication passage 72 are communicated. By driving the flow pump 52 , the liquid in the discharge side pressure regulating valve 41 and the return flow path 50 can be discharged through the return flow path 50 .

(9) In the liquid injection device 11a, the pressure in the discharge side liquid chamber 43 is adjusted to be lower than the second pressure in a state in which the first switching valve 71 is switched to the state in which the fluid introduction passage 70 and the atmosphere communication passage 72 are communicated. By driving the flow pump 52 , the atmosphere can be introduced into the discharge side liquid chamber 43 . For this reason, when ink that solidifies when the amount of oxygen in the liquid decreases is used as an example of the liquid, solidification of the liquid can be suppressed.

(10) Since the liquid ejecting apparatus 11a includes the degassing section 60, even when the air is introduced into the discharge-side liquid chamber 43, the liquid containing the air can be supplied to each liquid ejecting head 20. can be suppressed.

(11) In the liquid ejecting apparatus 11a, the flow path resistance of the second flow path R2 between the nozzle 21 and the discharge side liquid chamber 43 is equal to that of the first flow path R1 between the supply side liquid chamber 33 and the nozzle 21. smaller than the flow path resistance. Therefore, the difference between the pressure in the discharge side liquid chamber 43 and the pressure applied to the nozzle 21 can be reduced. Therefore, by adjusting the pressure in the discharge side liquid chamber 43, the pressure applied to the nozzle 21 can be adjusted with high accuracy.

(12) When the liquid is ejected from the nozzle 21, the liquid ejection device 11a facilitates the flow of liquid from the first common liquid chamber 22 to the ejection liquid chamber 23, and facilitates the flow of the liquid from the second common liquid chamber 27 to the ejection liquid chamber 23. It is possible to suppress the liquid from flowing into the Therefore, when the liquid is ejected from the nozzle 21, the liquid can flow into the ejection liquid chamber 23 from the liquid supply path 30 side.

(13) The discharge-side pressure regulating valve 41 reduces pressure fluctuations occurring inside each liquid jet head 20 when the liquid is discharged from the discharge-side liquid chamber 43 to the return channel 50 side in the circulation operation. Therefore, the liquid ejecting device 11a can reduce fluctuations in the pressure applied to the nozzles 21 during the circulation operation.

(14) The volume of the discharge side liquid chamber 43 in which the discharge side flexible portion 42 can be changed is larger than the volume of the supply side liquid chamber 33 in which the supply side flexible portion 32 can be changed. Therefore, even when a large amount of liquid is discharged from the discharge-side liquid chamber 43 to the return channel 50 side, the discharge-side pressure regulating valve 41 is closed by the displacement of the discharge-side flexible portion 42 . By reducing the volume of 43, fluctuations in the pressure in the discharge side liquid chamber 43 can be preferably reduced. Therefore, the liquid ejecting device 11a can suitably reduce the pressure fluctuations applied to the nozzle 21 .

(15) Each liquid jet head 20 and each supply-side pressure regulating valve 31 are held by the head holder 90 in a state in which they do not move relative to each other. Therefore, in the liquid ejecting apparatus 11a, when the head holder 90 is displaced, the distance in the vertical direction Z between the nozzle surface 21a and each of the supply-side pressure regulating valves 31 changes, so that the pressure applied to the nozzles 21 changes. can be suppressed.

(16) Each liquid jet head 20 and the discharge-side pressure regulating valve 41 are held by the head holder 90 in a state in which they do not move relative to each other. Therefore, in the liquid ejecting apparatus 11a, when the head holder 90 is displaced, the pressure applied to the nozzle 21 changes due to the change in the distance in the vertical direction Z between the nozzle surface 21a and the discharge side pressure regulating valve 41. can be suppressed.

(Second embodiment)
Next, a second embodiment of a liquid ejecting device and a method of controlling the liquid ejecting device will be described with reference to the drawings. The second embodiment does not include the discharge-side pressure regulating valve 41, the return flow path 50, and the fluid introduction path 70. This differs from the first embodiment in that the pressure applied to 21 is adjusted. Since other points are substantially the same as those of the first embodiment, the same components are denoted by the same reference numerals, thereby omitting redundant description.

As shown in FIG. 8 , the liquid discharge path 40 is connected between the degassing section 60 and the supply side pressure regulating valve 31 in the liquid supply path 30 . That is, the liquid discharge path 40 is connected to the upstream side liquid supply path 30 a of the liquid supply path 30 that is upstream of the supply side liquid chamber 33 .

The liquid ejecting apparatus 11 a has a liquid flow path from the degassing section 60 toward the first common liquid chamber 22 of each liquid ejecting head 20 at the connecting portion between the liquid discharge path 40 and the liquid supply path 30 . It is preferable to provide a third switching valve 110 capable of switching between 30 a and the liquid discharge path 40 . As an example, the third switching valve 110 connects the liquid discharge path 40 and the liquid discharge path 40 upstream of the connection portion of the upstream liquid supply path 30a to the liquid discharge path 40 of the upstream liquid supply path 30a. A three-way valve can be provided with three valve bodies capable of individually closing three flow paths downstream from the portion.

The liquid discharge path 40 branches between each liquid jet head 20 and the third switching valve 110, and is connected to the liquid storage section 15, which is an example of a liquid storage section. That is, the liquid discharge path 40 has a branching portion 40a. The liquid ejection device 11 a has a third on-off valve 120 as an example of a reservoir pressure adjustment mechanism provided between each liquid ejection head 20 and the liquid storage section 15 in the liquid discharge path 40 . The third on-off valve 120 closes the liquid discharge path 40 on the liquid storage section 15 side of the branch section 40a by being closed. In other words, the third on-off valve 120 opens the liquid storage section 15 and each liquid jet head 20 through the liquid discharge path 40 by opening the valve. That is, the third on-off valve 120 is in an open state, and causes the pressure in the liquid storage section 15 to act on the nozzle 21 through the liquid discharge path 40 . In one example of the present embodiment, the pressure inside the liquid containing portion 15 is determined by the pressure applied to the liquid surface of the liquid contained within the liquid containing portion 15 . The pressure within the liquid containing portion 15 may be determined by the pressure applied to any position within the liquid containing portion 15 .

The liquid ejecting device 11 a includes a pressure damper 121 between the branch portion 40 a of the liquid discharge passage 40 and the third on-off valve 120 to reduce fluctuations in the pressure inside the liquid discharge passage 40 . That is, the liquid ejecting apparatus 11 a includes a pressure damper 121 between each liquid ejecting head 20 and the third on-off valve 120 in the liquid discharge path 40 . The pressure damper 121 includes, for example, a pressure adjustment chamber 123 whose volume is changed by bending a pressure adjustment flexible portion 122 forming a wall portion. In the pressure damper 121, the pressure adjusting flexible portion 122 bends so as to increase the volume of the pressure adjusting chamber 123 when the amount of liquid in the liquid discharge passage 40 increases, while the liquid in the liquid discharge passage 40 is reduced. When the amount decreases, the pressure adjusting flexible portion 122 bends so as to reduce the volume of the pressure adjusting chamber 123 . As a result, the liquid ejecting device 11 a can reduce pressure fluctuations in the liquid discharge path 40 . The liquid ejecting apparatus 11 a includes a discharge flow pump 124 for flowing the liquid between the third on-off valve 120 and the liquid storage section 15 in the liquid discharge passage 40 .

The liquid ejecting device 11 a includes a holding portion 15 a that holds the liquid containing portion 15 . The liquid containing portion 15 is held by the holding portion 15a so that the position of the liquid surface in the liquid containing portion 15 in the vertical direction Z is within the range from the first position H1 to the second position H2. The first position H1 is the position of the liquid surface when the liquid containing portion 15 contains the maximum amount of liquid that can be contained. The second position H2 is the position of the liquid surface when the minimum amount of liquid that can be supplied from the liquid containing portion 15 to the liquid supply path 30 is contained.

In one example of the present embodiment, the first position H1 and the second position H2 are obtained as potential energy of the liquid in the liquid storage part 15 when the inside of the liquid storage part 15 is open to the atmosphere as shown in FIG. is the position of the liquid surface in the liquid containing portion 15 when the pressure is lower than the first pressure and the pressure is such that the gas-liquid interface formed in the nozzle 21 is maintained. That is, in one example of the present embodiment, the pressure in the liquid containing portion 15 is lower than the first pressure and the gas-liquid interface formed in the nozzle 21 is lower than the first pressure because the liquid containing portion 15 is held by the holding portion 15a. is adjusted to a second pressure at which is maintained. That is, the holding portion 15a holds the liquid storage portion 15 at a position where the pressure inside the liquid storage portion 15 acting on the nozzle 21 through the liquid discharge path 40 becomes the second pressure.

At this time, the difference between the pressure applied to the nozzle 21 and the pressure in the liquid containing portion 15 changes depending on the distance between the position of the nozzle surface 21 a in the vertical direction Z and the position of the liquid surface in the liquid containing portion 15 . Therefore, the pressure applied to the nozzle 21 when the position of the liquid surface in the liquid containing portion 15 is the first position H1 varies depending on the distance D3 between the position of the nozzle surface 21a and the first position H1 in the vertical direction Z. do. Further, the pressure applied to the nozzle 21 when the position of the liquid surface in the liquid containing portion 15 is the second position H2 changes depending on the distance D4 between the position of the nozzle surface 21a and the second position H2 in the vertical direction Z. .

In this embodiment, the controller 200 controls the third on-off valve 120 and the discharge flow pump 124 .
Next, a method of controlling the liquid ejecting device 11a by the controller 200 will be described.

The control unit 200 causes the pressure inside the liquid storage unit 15 to act on the nozzle 21 by opening the third on-off valve 120 . Here, the pressure inside the liquid containing portion 15 is adjusted to a second pressure that is lower than the first pressure and that maintains the gas-liquid interface formed in the nozzle 21 . Therefore, the control unit 200 causes the pressure inside the liquid storage unit 15 , which is adjusted to a second pressure that is lower than the first pressure and that maintains the gas-liquid interface formed in the nozzle 21 , to act on the nozzle 21 . to discharge the liquid in each liquid jet head 20 to the liquid discharge path 40 side.

Next, the circulation operation in this embodiment will be described.
The controller 200 drives the pressure pump 81 and the discharge pump 88 to supply the liquid in the liquid storage section 15 to the liquid supply path 30 side. That is, the pressurizing pump 81 and the discharge pump 88 cause the liquid stored in the liquid storage section 15 to flow toward the supply side pressure regulating valves 31 through the liquid supply path 30 . In this embodiment, the pressurizing pump 81 and the discharge pump 88 are an example of a liquid flow mechanism.

Subsequently, when the liquid in each liquid ejecting head 20 is to be discharged to the liquid discharge path 40 side, the control unit 200 opens the third on-off valve 120 so that the liquid containing part 15 is discharged through the liquid discharge path 40 . and each liquid jet head 20 are communicated with each other. According to this, the pressure inside the liquid containing portion 15 acts on the nozzles 21 of each liquid jet head 20 . Therefore, the liquid in each liquid ejecting head 20 can be discharged to the side of the liquid containing section 15 where the pressure is lower. That is, the control unit 200 controls the third on-off valve 120 to cause the pressure in the liquid storage unit 15 to act on the nozzles 21 through the liquid discharge paths 40, thereby causing the liquid in each liquid jet head 20 to move. The liquid is discharged to the liquid discharge path 40 side.

At this time, the pressure inside the liquid containing portion 15 is adjusted to the second pressure at which the gas-liquid interface formed in the nozzle 21 is maintained. Therefore, in the liquid ejecting device 11a, the meniscus can be maintained at the air-liquid interface of the nozzle 21 when circulating the liquid in the liquid ejecting device 11a.

After that, the control unit 200 closes the third on-off valve 120 to disconnect the liquid storage unit 15 and each liquid jet head 20 . As described above, the liquid ejecting device 11a can circulate the liquid in the liquid ejecting device 11a.

Next, the operation of the liquid injection device 11a of this embodiment will be described.
The holding part 15 a adjusts the pressure inside the liquid containing part 15 to a pressure that can maintain the meniscus at the air-liquid interface of the nozzle 21 by holding the liquid containing part 15 at a predetermined position. Then, when performing a circulation operation for circulating the liquid in the liquid injection device 11a, the control section 200 causes the pressure in the liquid storage section 15 to act on the nozzle 21 by opening the third on-off valve 120 . That is, the pressure applied to the nozzle 21 during the circulation operation is adjusted to a pressure that can maintain the meniscus at the air-liquid interface of the nozzle 21 .

Effects of the present embodiment will be described.
(17) Since the liquid ejecting apparatus 11a has the supply-side pressure regulating valve 31 on the side of the liquid supply path 30 that supplies the liquid to each liquid ejecting head 20, the pressure inside the liquid storage section 15 connected to the liquid discharge path 40 can be adjusted to adjust the pressure in the nozzle 21 . Therefore, the liquid ejecting device 11a can prevent the pressure control from becoming complicated when performing the circulation operation for circulating the liquid.

(18) The liquid ejecting apparatus 11 a can easily perform a circulation operation for discharging the liquid in each liquid ejecting head 20 to the liquid discharge path 40 side by opening and closing the third on-off valve 120 .
(19) Since the liquid ejecting apparatus 11a includes the pressure damper 121 between each liquid ejecting head 20 and the third on-off valve 120 in the liquid discharge path 40, the pressure when opening and closing the third on-off valve 120 is Fluctuation acting on each liquid jet head 20 can be reduced.

(20) The liquid ejecting apparatus 11a adjusts the pressure on the side of the liquid supply path 30 to the first pressure by means of the pressurized liquid supply path 30 and the supply-side pressure regulating valve 31, and discharges the liquid depending on the position of the liquid containing portion 15. The pressure on the side of line 40 can be adjusted to a second pressure.

(21) According to the control method by the control unit 200, the pressure inside the liquid storage unit 15 is adjusted to a second pressure that is lower than the first pressure and does not break the gas-liquid interface formed in the nozzle 21. By acting on the nozzles 21 through the liquid discharge paths 40, the liquid in each liquid jet head 20 can be discharged to the liquid discharge path 40 side. Therefore, it is possible to prevent the pressure control from becoming complicated when performing the circulation operation for circulating the liquid.

(22) According to the control method by the control unit 200, by opening the third on-off valve 120, the second pressure is lower than the first pressure and does not break the gas-liquid interface formed in the nozzle 21. The adjusted pressure inside the liquid containing portion 15 is applied to the nozzle 21 via the liquid discharge path 40 . Therefore, it is possible to prevent the pressure control from becoming complicated when performing the circulation operation for circulating the liquid.

(Third Embodiment)
Next, a liquid ejecting apparatus according to a third embodiment will be described with reference to the drawings. The third embodiment differs from the first embodiment in that the discharge side pressure regulating valve 41 is not held by the head holder 90 and the bypass passage 73 is not provided. Since other points are substantially the same as those of the first embodiment, the same components are denoted by the same reference numerals, thereby omitting redundant description.

As shown in FIGS. 9 and 10, the discharge side pressure regulating valve 41 is provided at a position where the center position of the pressure of the discharge side liquid chamber 43 is lower than the nozzle surface 21a in the vertical direction Z by a distance D5. there is Further, the discharge side pressure regulating valve 41 is provided at a position where the pressure center position of the discharge side liquid chamber 43 is lower than the pressure center position of the supply side liquid chamber 33 in the vertical direction Z by a distance D6. . The discharge side pressure regulating valve 41 is provided outside the head holder 90 . That is, the discharge side pressure regulating valve 41 is configured so that the position of the discharge side liquid chamber 43 in the vertical direction Z does not change even when the head holder 90 is displaced along the vertical direction Z.

The fluid introduction path 70 is connected to the atmosphere communication path 72 . The liquid injection device 11a also includes a fourth on-off valve 130 that shuts off the fluid introduction passage 70 and the air communication passage 72 by closing the valve. The fourth on-off valve 130 is provided above the nozzle surface 21a in the vertical direction Z. As shown in FIG. An open end 72a of the atmosphere communication passage 72 that is open to the atmosphere is provided above the nozzle surface 21a in the vertical direction Z. As shown in FIG.

Next, the operation of the liquid injection device 11a of this embodiment will be described.
The position of the discharge-side liquid chamber 43 in the vertical direction Z does not change even if the head holder 90 is displaced along the vertical direction Z. Therefore, the pressure in the discharge side liquid chamber 43 does not change even when the head holder 90 is displaced along the vertical direction Z.

In addition, the fourth on-off valve 130 and the open end 72a of the air communication passage 72 are provided above the nozzle surface 21a in the vertical direction Z. As shown in FIG. Therefore, when the fourth on-off valve 130 is opened, the gas-liquid interface in the flow path formed by the fluid introduction path 70 and the air communication path 72 is formed below the fourth on-off valve 130 . be.

Effects of the present embodiment will be described.
(23) Since the pressure in the discharge side liquid chamber 43 does not change even when the head holder 90 is displaced along the vertical direction Z, the pressure in the discharge side liquid chamber 43 can be accurately controlled.

(24) When the fourth on-off valve 130 is open, the gas-liquid interface in the flow path formed by the fluid introduction path 70 and the air communication path 72 is formed below the fourth on-off valve 130. be done. Therefore, leakage of liquid from the open end 72a of the atmospheric communication passage 72 can be suppressed.

(Fourth embodiment)
Next, a fourth embodiment of the liquid injection device will be described with reference to the drawings. In this fourth embodiment, instead of the supply-side pressure regulating valve 31, a supply-side liquid reservoir 140 capable of storing liquid and the pressure inside the supply-side liquid reservoir 140 are adjusted as a supply-side pressure adjustment mechanism. It is different from the case of the first embodiment in that a supply side reservoir pressure adjustment mechanism 141 is provided. Since other points are substantially the same as those of the first embodiment, the same components are denoted by the same reference numerals, thereby omitting redundant description.

As shown in FIG. 11 , the supply-side liquid reservoir 140 is provided between the temporary reservoir 80 and each liquid jet head 20 in the liquid supply path 30 . The supply-side liquid storage section 140 communicates with the temporary storage section 80 via the liquid supply path 30 and also communicates with each liquid jet head 20 .

Supply-side reservoir pressure adjustment mechanism 141 can adjust the pressure in supply-side liquid reservoir 140 by adjusting the amount of gas in supply-side liquid reservoir 140 . In one example of this embodiment, the pressure in the supply-side liquid reservoir 140 is determined by the gas pressure at a predetermined position in the supply-side liquid reservoir 140 . The pressure within the supply side liquid reservoir 140 may be determined by the pressure applied to any position within the supply side liquid reservoir 140 . As an example, the pressure in the supply-side liquid reservoir 140 may be determined by the pressure applied to the liquid surface of the liquid contained in the supply-side liquid reservoir 140, or the pressure applied to the bottom surface of the supply-side liquid reservoir 140. It may be defined by pressure.

In one example of the present embodiment, the supply-side reservoir pressure adjustment mechanism 141 includes an atmosphere open path 141a having one end connected to the supply-side liquid reservoir 140 and the other end open to the atmosphere, and a gas discharge pump 141c that drives the gas in the supply-side liquid reservoir 140 so as to discharge the gas. The supply-side reservoir pressure adjustment mechanism 141 also includes an atmosphere release valve 141d that closes the atmosphere release path 141a by closing the valve. It should be noted that the pressure gauge 141b is preferably a relative pressure gauge that measures the differential pressure with respect to the atmospheric pressure.

Then, when the pressure in the supply-side liquid reservoir 140 measured by the pressure gauge 141b is higher than the first pressure, the controller 200 opens the air release valve 141d and drives the gas discharge pump 141c. , the gas in the supply-side liquid storage section 140 is discharged and the pressure in the supply-side liquid storage section 140 is reduced.

Next, the operation of the liquid injection device 11a of this embodiment will be described.
The supply-side liquid reservoir 140 is in communication with the temporary reservoir 80 via the liquid supply path 30 and with each liquid ejecting head 20 , thereby reservoiring the liquid supplied from the temporary reservoir 80 . At the same time, the stored liquid is supplied to each liquid jet head 20 . Further, since the supply-side liquid reservoir 140 and each liquid jet head 20 are in communication, the pressure applied to the nozzles 21 of each liquid jet head 20 fluctuates according to the pressure inside the supply-side liquid reservoir 140. .

Then, when the pressure in the supply-side liquid reservoir 140 is higher than the first pressure, the controller 200 decompresses the inside of the supply-side liquid reservoir 140 so that the liquid level in the supply-side liquid reservoir 140 becomes By controlling the acting gas pressure to be low, the pressure in the supply side liquid reservoir 140 is adjusted to the first pressure or lower.

Effects of the present embodiment will be described.
(25) The liquid ejecting apparatus 11a can adjust the pressure in the supply-side liquid storage section 140 to be equal to or lower than the first pressure under the control of the control section 200, so the pressure applied to the nozzle 21 can be adjusted with high accuracy.

(Fifth embodiment)
Next, a fifth embodiment of a liquid ejecting apparatus and a method of controlling the liquid ejecting apparatus will be described with reference to the drawings. The fifth embodiment differs from the second embodiment in that it includes a secondary liquid storage section 150 provided in the liquid discharge path 40 and capable of storing liquid as a liquid storage section. Since other points are substantially the same as those of the second embodiment, the same reference numerals are given to the same configurations to omit redundant description.

As shown in FIG. 12 , the secondary liquid storage section 150 is provided between the third on-off valve 120 and the liquid storage section 15 in the liquid discharge path 40 . The secondary liquid storage section 150 communicates with each liquid jet head 20 via the liquid discharge path 40 and communicates with the liquid storage section 15 via the liquid discharge path 40 . Further, the liquid ejection device 11a includes a fifth on-off valve 151 that closes the liquid discharge path 40 by closing the liquid discharge path 40 between the sub liquid storage part 150 and the liquid storage part 15. . Further, the liquid ejecting device 11a includes a sub-holding portion 152 that holds the sub-liquid storage portion 150 as an example of a reservoir pressure adjusting mechanism.

The secondary liquid storage section 150 may be held by the secondary holding section 152 so that the position of the liquid surface in the secondary liquid storage section 150 in the vertical direction Z is within the range from the third position H3 to the fourth position H4. good. The third position H3 is the position of the liquid surface when the secondary liquid storage portion 150 stores the maximum amount of liquid that can be stored. The fourth position H4 is the position of the liquid surface when the minimum amount of liquid that can be supplied from the sub-liquid storage section 150 to each liquid jet head 20 and the liquid storage section 15 is stored.

In one example of the present embodiment, the position of the liquid surface in the secondary liquid storage section 150 within the range from the third position H3 to the fourth position H4 is When the pressure as the potential energy of the liquid in the sub-liquid storage part 150 is lower than the first pressure and the pressure is such that the gas-liquid interface formed in the nozzle 21 is maintained, the pressure in the sub-liquid storage part 150 position of the liquid surface. That is, in one example of the present embodiment, the pressure in the secondary liquid storage section 150 is lower than the first pressure and formed in the nozzle 21 by holding the secondary liquid storage section 150 by the secondary holding section 152. A second pressure is adjusted at which the gas-liquid interface is maintained. That is, the sub-holding part 152 holds the sub-liquid storage part 150 at a position where the pressure in the sub-liquid storage part 150 acting on the nozzle 21 through the liquid discharge path 40 becomes the second pressure. In one example of the present embodiment, the pressure inside the secondary liquid storage section 150 is determined by the gas pressure at a predetermined position inside the secondary liquid storage section 150 . The pressure within the secondary liquid storage section 150 may be determined by the pressure applied to any position within the secondary liquid storage section 150 . As an example, the pressure in the secondary liquid storage section 150 may be determined by the pressure applied to the liquid surface of the liquid stored in the secondary liquid storage section 150, or determined by the pressure applied to the bottom surface of the secondary liquid storage section 150. may be

At this time, the difference between the pressure applied to the nozzle 21 and the pressure in the secondary liquid storage section 150 changes depending on the distance between the position of the nozzle surface 21 a in the vertical direction Z and the position of the liquid surface in the secondary liquid storage section 150 . Therefore, the pressure applied to the nozzle 21 when the position of the liquid surface in the sub-liquid storage section 150 is the third position H3 is determined by the distance D7 between the position of the nozzle surface 21a in the vertical direction Z and the third position H3. Change. Further, the pressure applied to the nozzle 21 when the position of the liquid surface in the liquid containing portion 15 is the fourth position H4 changes depending on the distance D8 between the position of the nozzle surface 21a in the vertical direction Z and the fourth position H4. .

The liquid ejecting apparatus 11a also includes a gas amount adjustment mechanism 153 that adjusts the pressure in the secondary liquid storage section 150 by adjusting the amount of gas in the secondary liquid storage section 150, as an example of the reservoir pressure adjustment mechanism. .

The gas amount adjusting mechanism 153 includes a sub-atmosphere opening channel 153a, one end of which is connected to the sub-liquid storage section 150 and the other end of which is open to the atmosphere, a sub-pressure gauge 153b that measures the pressure inside the sub-liquid storage section 150, and a gas amount adjustment pump 153c that drives the amount of gas in the sub-liquid storage unit 150 so as to be adjustable. Further, the gas amount adjustment mechanism 153 includes a sub-atmosphere release valve 153d that closes the sub-atmosphere release passage 153a by closing the valve. It should be noted that the secondary pressure gauge 153b is preferably a relative pressure gauge that measures the differential pressure with respect to the atmospheric pressure.

Then, when the pressure in the sub-liquid storage unit 150 measured by the sub-pressure gauge 153b is not the second pressure, the control unit 200 opens the sub-atmosphere release valve 153d and drives the gas amount adjustment pump 153c. to adjust the amount of gas in the secondary liquid storage section 150 and control the pressure in the secondary liquid storage section 150 to the second pressure.

Next, the operation of the liquid injection device 11a of this embodiment will be described.
The pressure in the secondary liquid storage section 150 is adjusted to a second pressure that can maintain the meniscus at the gas-liquid interface of the nozzle 21 by holding the secondary liquid storage section 150 at a predetermined position by the secondary holding section 152 . . In other words, the sub holding part 152 holds the sub liquid storage part 150 at a predetermined position, thereby adjusting the pressure inside the sub liquid storage part 150 to the second pressure that can maintain the meniscus at the air-liquid interface of the nozzle 21 . do. When performing a circulation operation for circulating the liquid in the liquid injection device 11 a , the control section 200 causes the pressure in the secondary liquid storage section 150 to act on the nozzle 21 by opening the third on-off valve 120 . That is, the pressure applied to the nozzle 21 during the circulation operation is adjusted to a pressure that can maintain the meniscus at the air-liquid interface of the nozzle 21 .

Further, when the pressure in the secondary liquid storage section 150 is not the second pressure, the control section 200 controls the gas amount adjustment mechanism 153 to reduce the pressure in the secondary liquid storage section 150 to the second pressure. adjust.

Next, a method of controlling the liquid ejecting device 11a by the controller 200 will be described.
When the liquid in each liquid jet head 20 is discharged to the liquid discharge path 40 side, the control section 200 executes a step of measuring the pressure in the secondary liquid storage section 150 with the secondary pressure gauge 153b. Subsequently, the control unit 200 opens the sub-atmosphere release valve 153d according to the measured pressure and drives the gas amount adjustment pump 153c to lower the pressure in the sub-liquid storage unit 150 below the first pressure. Then, a step of adjusting the pressure to a second pressure at which the gas-liquid interface formed in the nozzle 21 is maintained is executed. After that, the control unit 200 executes a step of opening the third on-off valve 120 . With such a control method, the control section 200 causes the pressure inside the secondary liquid storage section 150 to act on the nozzle 21 during the circulation operation. That is, the control unit 200 causes the pressure inside the secondary liquid storage unit 150 , which is adjusted to the second pressure lower than the first pressure and at which the gas-liquid interface formed in the nozzle 21 is maintained, to act on the nozzle 21 . to discharge the liquid in each liquid jet head 20 to the liquid discharge path 40 side.

In the circulating operation, the secondary air release valve 153d is opened to open the interior of the secondary liquid storage section 150 to the atmosphere, and the interior of the secondary liquid storage section 150 is adjusted within the range from the third position H3 to the fourth position H4. is applied to the nozzles 21 to discharge the liquid in each liquid jet head 20 to the liquid discharge path 40 side, the control unit 200 operates the reservoir pressure adjustment mechanism and each on-off valve as follows. may be controlled.

For example, when the level of the liquid in the secondary liquid container 150 is higher than the third position H3 in the vertical direction Z, the controller 200 closes the third on-off valve 120 and closes the fifth on-off valve 151. In the open state, the secondary air release valve 153d is opened and the gas amount adjustment pump 153c is driven to pressurize the interior of the secondary liquid storage section 150. 15, adjusts the level of the liquid in the secondary liquid container 150 to the fourth position H4, stops driving the gas amount adjustment pump 153c, and closes the fifth on-off valve 151. and

Further, for example, when the position of the liquid surface of the liquid in the secondary liquid storage section 150 is lower than the fourth position H4 in the vertical direction Z, the control section 200 closes the third on-off valve 120 and closes the fifth on-off valve. With the valve 151 in the open state, the secondary air release valve 153d is opened and the gas amount adjustment pump 153c is driven to reduce the pressure in the secondary liquid storage section 150. The liquid is allowed to flow into the portion 150, the level of the liquid in the sub-liquid storage portion 150 is adjusted to the fourth position H4, the gas amount adjustment pump 153c is stopped, and the fifth on-off valve 151 is closed. valve state. Then, when the liquid in each liquid jet head 20 is discharged to the liquid discharge path 40 side to perform the circulation operation, the control unit 200 closes the third on-off valve 120 while opening the secondary air release valve 153d. state.

Effects of the present embodiment will be described.
(26) The liquid ejecting device 11a can adjust the pressure in the nozzle 21 by adjusting the pressure in the secondary liquid storage section 150 connected to the liquid discharge path 40 . Therefore, the liquid ejecting device 11a can prevent the pressure control from becoming complicated when performing the circulation operation for circulating the liquid.

(27) Since the liquid ejecting device 11a can adjust the pressure inside the secondary liquid storage section 150 to the second pressure under the control of the control section 200, the pressure applied to the nozzle 21 can be adjusted with high accuracy.
(28) According to the control method by the control unit 200, the pressure in the sub-liquid storage unit 150 is adjusted to a second pressure that is lower than the first pressure and does not break the gas-liquid interface formed in the nozzle 21. , the liquid in each liquid ejecting head 20 can be discharged to the liquid discharge path 40 side by acting on the nozzles 21 via the liquid discharge path 40 . Therefore, it is possible to prevent the pressure control from becoming complicated when performing the circulation operation for circulating the liquid.

(29) According to the control method by the control unit 200, by opening the third on-off valve 120, the second pressure is lower than the first pressure and does not break the gas-liquid interface formed in the nozzle 21. The adjusted pressure inside the secondary liquid storage section 150 is applied to the nozzle 21 via the liquid discharge path 40 . Therefore, it is possible to prevent the pressure control from becoming complicated when performing the circulation operation for circulating the liquid.

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.
Recording may be performed by ejecting the liquid onto the paper 14 as the recording medium from the liquid ejecting section 12 while the liquid in the liquid ejecting device 11a is being circulated.

The flow path between the supply-side liquid chamber 33 of each supply-side pressure regulating valve 31 and the nozzle 21 of each liquid jet head 20 in the second embodiment is the first flow path, and the flow path between the nozzle 21 and the liquid containing portion 15 is is used as the second flow path, the flow path resistance of the second flow path may be smaller than the flow path resistance of the first flow path, as in the first embodiment.

The flow path between the supply-side liquid chamber 33 of each supply-side pressure regulating valve 31 and the nozzle 21 of each liquid jet head 20 in the fifth embodiment is the first flow path, and the flow path between the nozzle 21 and the secondary liquid storage section 150 is When the intervening channel is the second channel, the channel resistance of the second channel may be smaller than the channel resistance of the first channel, as in the first embodiment.

- As shown in FIGS. 2, 9, and 10, in the first, third, and fourth embodiments, the posture of the discharge side pressure regulating valve 41 can be changed as appropriate. As an example, as shown in FIG. 2 , the discharge side pressure regulating valve 41 may be provided in such a posture that the discharge side flexible portion 42 is the bottom surface of the discharge side liquid chamber 43 . Further, as shown in FIGS. 9 and 10, the discharge side pressure regulating valve 41 may be provided in such a posture that the discharge side flexible portion 42 serves as the side wall of the discharge side liquid chamber 43. FIG. That is, in the discharge side pressure regulating valve 41, in the discharge side liquid chamber 43, the second communication hole 43b that communicates with the liquid discharge path 40 is located in the vertical direction Z more than the first communication hole 43a that communicates with the first discharge side communication chamber 44. , and communicated with the return flow path 50 may be provided in a posture in which the third communication hole 43c is positioned above the first communication hole 43a in the vertical direction Z.

- In the third embodiment, the fluid introduction path 70 may be connected to the atmosphere communication path 72 and the bypass flow path 73 via the first switching valve 71 . In this case, the first switching valve 71 and the open end 72a of the atmospheric communication passage 72 are preferably provided above the nozzle surface 21a in the vertical direction Z. Also, the fluid introduction path 70 may be connected to the bypass flow path 73 but not connected to the atmosphere communication path 72 .

- In the fifth embodiment, the control unit 200 opens and closes the secondary air release valve 153d and the gas amount adjustment pump 153c so that the pressure in the secondary liquid storage unit 150 measured by the secondary pressure gauge 153b becomes the second pressure. While controlling the driving of , the pressure in the sub-liquid storage section 150 may be applied to the nozzles 21 to discharge the liquid in each liquid jet head 20 to the liquid discharge path 40 side. In this case, the position of the liquid surface in the secondary liquid container 150 in the vertical direction Z does not have to be adjusted within the range from the third position H3 to the fourth position H4.

- In the fifth embodiment, by providing either one of the sub-holding portion 152 that holds the sub-liquid storage portion 150 and the gas amount adjustment mechanism 153 that adjusts the pressure in the sub-liquid storage portion 150, the sub- The pressure inside the liquid containing portion 150 may be adjusted to the second pressure.

In the fifth embodiment, if the gas amount adjusting mechanism 153 for adjusting the pressure in the secondary liquid storage section 150 is not provided, the secondary liquid storage section 150 is arranged in the same manner as the liquid storage section 15 in FIG. A liquid level detection sensor is provided to detect the liquid level in the secondary liquid storage section 150, and the position of the liquid level in the secondary liquid storage section 150 in the vertical direction Z is from the third position H3. You may adjust so that it may be in the range of the 4th position H4. For example, when it is detected that the liquid flows into the sub-liquid storage section 150 through the liquid discharge path 40 due to the circulation operation and the liquid level reaches the third position H3, the control section 200 With the third on-off valve 120 closed and the fifth on-off valve 151 and the second on-off valve 89 open, the discharge pump may be driven until the liquid level reaches the fourth position H4. good. Further, for example, when it is detected that the liquid flows into the sub-liquid storage section 150 through the liquid discharge path 40 due to the circulation operation and the position of the liquid surface reaches the third position H3, the control section 200 The fifth on-off valve 151 is opened while the third on-off valve 120 is closed, and the liquid storage section 15 is arranged below the secondary liquid storage section 150 in the vertical direction Z. The liquid in the sub-liquid storage portion 150 may be caused to flow into the liquid storage portion 15, and the fifth on-off valve 151 may be closed when it is detected that the liquid level has reached the fourth position H4.

- Deaeration of the liquid is not limited to decompression through the hollow fiber membrane 61, and any method such as ultrasonic deaeration or centrifugal deaeration can be adopted.
- In the pressurized cleaning process, instead of releasing the capping in step S21, the cap release valve 101a may be opened. According to this configuration, since pressure cleaning can be performed while capping is being performed, scattering of the liquid flowing out from the nozzles 21 can be suppressed.

- The recording medium is not limited to the paper 14, and may be cloth, plastic film, or metal film.
The control unit 200 can be realized by software using a CPU that executes a program, or can be implemented by hardware using electronic circuits (for example, semiconductor integrated circuits) such as FPGAs (field-programmable gate arrays) and ASICs (Application Specific ICs). Alternatively, it may be realized by cooperation of software and hardware.

The liquid ejected by each liquid ejecting head 20 is not limited to ink, and may be, for example, a liquid material in which particles of a functional material are dispersed or mixed in liquid. For example, each liquid ejecting head 20 may eject a liquid containing dispersed or dissolved materials such as electrode materials or pixel materials used in the manufacture of liquid crystal displays, electroluminescence displays and surface emitting displays.

The technical ideas and effects obtained from the above-described embodiments and modifications will be described below.
A liquid ejecting apparatus includes a liquid ejecting head having a nozzle surface in which a nozzle for ejecting liquid opens; a liquid supply path connected to a liquid inlet of the liquid ejecting head and supplying the liquid to the liquid ejecting head; a liquid discharge passage connected to a liquid outlet of a liquid jet head for discharging the liquid from the liquid jet head; a supply-side pressure adjusting mechanism capable of adjusting a first pressure at which a liquid interface is maintained; and a discharge-side liquid chamber provided in the liquid discharge passage and connected to the liquid outlet, and the discharge-side liquid chamber is lower than the pressure outside the discharge-side liquid chamber and the first pressure, and becomes a second pressure at which the gas-liquid interface formed in the nozzle is maintained, the valve is opened and the A discharge-side valve element is provided for communicating a discharge-side liquid chamber and a fluid introduction path capable of introducing fluid into the discharge-side liquid chamber from outside the discharge-side liquid chamber, and the pressure of the liquid supplied to the liquid jet head is reduced. a discharge side pressure regulating valve that adjusts the pressure to maintain a gas-liquid interface formed in the nozzle; a flow mechanism connected to the discharge-side liquid chamber by a return flow path so as to be able to discharge to the discharge path side.

According to this configuration, the liquid ejecting apparatus has the ejection side pressure regulating valve in the liquid ejection passage for ejecting the liquid from the liquid ejecting head. Therefore, the liquid ejecting apparatus can reduce pressure fluctuations in the nozzle when discharging the liquid from the liquid outlet by driving the flow mechanism in the circulation operation for circulating the liquid. Therefore, the liquid ejecting apparatus can prevent the pressure control from becoming complicated when performing the circulation operation.

In the liquid ejecting apparatus, the supply-side pressure adjusting mechanism has the supply-side liquid chamber, and the pressure inside the supply-side liquid chamber becomes the first pressure lower than the pressure outside the supply-side liquid chamber. pressure of the liquid supplied to the liquid ejecting head, the pressure of the liquid being supplied to the liquid ejecting head. may be a supply-side pressure regulating valve that adjusts the pressure to maintain the gas-liquid interface formed in the nozzle.

According to this configuration, the liquid injection device can adjust the pressure of the supply-side liquid chamber by the supply-side pressure regulating valve. Therefore, the liquid ejecting apparatus can easily control the pressure of the supply-side liquid chamber as compared with the case where the pressure of the supply-side liquid chamber is adjusted using, for example, a pump and a sensor.

In the liquid injection device, the supply-side pressure regulating valve includes a supply-side flexible portion that forms a wall portion of the supply-side liquid chamber and bends when the pressure in the supply-side liquid chamber fluctuates, and the supply-side valve body. and a supply-side biasing member that biases the valve in the closing direction.

According to this configuration, the liquid injection device can reduce pressure fluctuations in the supply-side liquid chamber by flexing the supply-side flexible portion, thereby facilitating pressure control of the supply-side liquid chamber.
In the above-described liquid injection device, the discharge side pressure regulating valve includes a discharge side flexible portion that forms a wall portion of the discharge side liquid chamber and bends when the pressure in the discharge side liquid chamber fluctuates, and the discharge side valve body. and a discharge-side biasing member that biases the valve in the closing direction.

According to this configuration, the liquid ejecting apparatus can reduce pressure fluctuations in the discharge-side liquid chamber by bending the discharge-side flexible portion, so that it is possible to easily control the pressure in the discharge-side liquid chamber.
In the above-described liquid injection device, the liquid discharge path connecting the liquid outlet and the discharge side liquid chamber of the discharge side pressure regulating valve allows the fluid flowing from the fluid introduction path to flow into the discharge side liquid chamber. The discharge side liquid chamber may be opened at a position below the position.

According to this configuration, the liquid ejecting device can prevent the fluid that has flowed from the fluid introduction path into the discharge-side liquid chamber from flowing into the liquid discharge path.
In the above-described liquid injection device, the return flow path connecting the discharge side liquid chamber of the discharge side pressure regulating valve and the flow mechanism is positioned at a position where the fluid flowing from the fluid introduction path flows into the discharge side liquid chamber. The discharge side liquid chamber may be opened at a higher position.

According to this configuration, the liquid ejecting apparatus can efficiently discharge the fluid that has flowed into the discharge-side liquid chamber from the fluid introduction path from the discharge-side liquid chamber via the return flow path.
In the liquid injection device, the fluid introduction path connects the discharge side liquid chamber of the discharge side pressure regulating valve and an upstream liquid supply path upstream of the supply side liquid chamber of the liquid supply path. good too.

According to this configuration, the liquid ejecting apparatus introduces the same liquid as the liquid supplied to the liquid ejecting head into the ejection side liquid chamber when the pressure in the ejection side liquid chamber reaches the second pressure. pressure can be maintained.

In the liquid injection device, the fluid introduction path may be configured to introduce gas into the discharge-side liquid chamber of the discharge-side pressure regulating valve.
According to this configuration, when the liquid in the discharge side pressure regulating valve and the return flow path is discharged, the liquid injection device drives the flow mechanism so that the pressure in the discharge side liquid chamber becomes lower than the second pressure. It can be discharged via a return channel.

DESCRIPTION OF SYMBOLS 11... Recording apparatus 11a... Liquid ejecting apparatus 12... Liquid ejecting part 15... Liquid containing part 15a... Holding part 20... Liquid ejecting head 21... Nozzle 21a... Nozzle surface 22... First common liquid chamber , 22a... Liquid inlet 22b... First communication passage 23... Injection liquid chamber 24... Diaphragm 25... Actuator 26... Accommodating chamber 27... Second common liquid chamber 27a... Liquid outlet 27b... Second communication path 30 Liquid supply path 30a Upstream liquid supply path 31 Supply side pressure regulating valve 32 Supply side flexible portion 32a Supply side inner surface 32b Supply side outer surface 33 Supply Liquid side chamber 34 Supply side communication chamber 35 Supply side valve body 36 Supply side biasing member 40 Liquid discharge path 40a Branch portion 41 Discharge side pressure regulating valve 42 Discharge side possible Flexible portion 42a...Inner surface on the discharge side 42b...Outer surface on the discharge side 43...Discharge side liquid chamber 43a...First communication hole 43b...Second communication hole 43c...Third communication hole 44...First discharge side communication Chamber 45 Second discharge-side communication chamber 46 Discharge-side valve body 47 Discharge-side biasing member 50 Return flow path 51 First on-off valve 52 Fluid pump 70 Fluid introduction path 71 First switching valve 72 Atmospheric communication passage 72a Open end 73 Bypass passage 74 Second switching valve 81 Pressure pump 88 Discharge pump 90 Head holder 120 Second 3 on-off valves 121 pressure damper 122 pressure-regulating flexible portion 123 pressure-regulating chamber 124 discharge flow pump 130 fourth on-off valve 140 supply-side liquid reservoir 141 supply-side reservoir partial pressure adjusting mechanism 141a atmospheric release passage 141b pressure gauge 141c gas discharge pump 141d atmospheric release valve 150 secondary liquid storage section 151 fifth opening/closing valve 152 secondary holding section 153 Gas volume adjustment mechanism 153a Sub-atmosphere release passage 153b Sub-pressure gauge 153c Gas volume adjustment pump 153d Sub-atmosphere release valve 200 Control unit.

Claims (9)

a liquid jet head having a nozzle surface on which nozzles for jetting liquid are opened;
a liquid supply path connected to the liquid inlet of the liquid ejecting head and supplying the liquid to the liquid ejecting head;
a liquid discharge path connected to a liquid outlet of the liquid jet head for discharging the liquid from the liquid jet head;
a supply-side pressure adjusting mechanism capable of adjusting the pressure inside the supply-side liquid chamber provided in the liquid supply path to a first pressure at which the gas-liquid interface formed in the nozzle is maintained;
a discharge-side liquid chamber provided in the liquid discharge path and connected to the liquid outlet, wherein the pressure in the discharge-side liquid chamber is lower than the pressure outside the discharge-side liquid chamber and the first pressure; Further, when the gas-liquid interface formed in the nozzle reaches a second pressure at which the gas-liquid interface is maintained, the valve can be opened to introduce fluid into the discharge-side liquid chamber and the discharge-side liquid chamber from outside the discharge-side liquid chamber. a discharge-side valve body that communicates with the fluid introduction path, and a discharge-side pressure adjustment that adjusts the pressure of the liquid supplied to the liquid jet head to a pressure that maintains the gas-liquid interface formed in the nozzle. a valve;
a flow mechanism connected to the discharge-side liquid chamber by a return flow path so as to be able to discharge the liquid in the liquid jet head to the liquid discharge path side through the discharge-side liquid chamber of the discharge-side pressure regulating valve; prepared,
The supply-side pressure adjustment mechanism has the supply-side liquid chamber, and opens when the pressure inside the supply-side liquid chamber reaches the first pressure lower than the pressure outside the supply-side liquid chamber. a supply-side valve body that communicates the supply-side liquid chamber with the liquid supply path on the upstream side of the supply-side liquid chamber;
A liquid ejecting apparatus, comprising: a supply-side pressure regulating valve that adjusts the pressure of the liquid supplied to the liquid ejecting head to a pressure that maintains a gas-liquid interface formed in the nozzle. The supply-side pressure regulating valve includes a supply-side flexible portion that constitutes a wall portion of the supply-side liquid chamber and bends when the pressure in the supply-side liquid chamber fluctuates, and 2. The liquid ejecting apparatus according to claim 1 , further comprising a supply-side biasing member that biases. The discharge-side pressure regulating valve includes a discharge-side flexible portion that forms a wall portion of the discharge-side liquid chamber and bends when the pressure in the discharge-side liquid chamber fluctuates, and a direction in which the discharge-side valve element closes. 3. The liquid ejecting apparatus according to claim 1 , further comprising a discharge-side biasing member that biases. The liquid discharge path connecting the liquid outlet and the discharge side liquid chamber of the discharge side pressure regulating valve is positioned below a position where the fluid flowing from the fluid introduction path flows into the discharge side liquid chamber. 4. The liquid ejecting apparatus according to any one of claims 1 to 3 , wherein the discharge side liquid chamber is opened at . The return flow path connecting the discharge-side liquid chamber of the discharge-side pressure regulating valve and the flow mechanism,
5. The discharge side liquid chamber is opened at a position above a position where the fluid flowing from the fluid introduction path flows into the discharge side liquid chamber. 3. The liquid injection device according to . a liquid jet head having a nozzle surface on which nozzles for jetting liquid are opened;
a liquid supply path connected to the liquid inlet of the liquid ejecting head and supplying the liquid to the liquid ejecting head;
a liquid discharge path connected to a liquid outlet of the liquid jet head for discharging the liquid from the liquid jet head;
a supply-side pressure adjusting mechanism capable of adjusting the pressure inside the supply-side liquid chamber provided in the liquid supply path to a first pressure at which the gas-liquid interface formed in the nozzle is maintained;
a discharge-side liquid chamber provided in the liquid discharge path and connected to the liquid outlet, wherein the pressure in the discharge-side liquid chamber is lower than the pressure outside the discharge-side liquid chamber and the first pressure; Further, when the gas-liquid interface formed in the nozzle reaches a second pressure at which the gas-liquid interface is maintained, the valve can be opened to introduce fluid into the discharge-side liquid chamber and the discharge-side liquid chamber from outside the discharge-side liquid chamber. a discharge-side valve body that communicates with the fluid introduction path, and a discharge-side pressure adjustment that adjusts the pressure of the liquid supplied to the liquid jet head to a pressure that maintains the gas-liquid interface formed in the nozzle. a valve;
a flow mechanism connected to the discharge-side liquid chamber by a return flow path so as to be able to discharge the liquid in the liquid jet head to the liquid discharge path side through the discharge-side liquid chamber of the discharge-side pressure regulating valve; prepared,
The return flow path connecting the discharge-side liquid chamber of the discharge-side pressure regulating valve and the flow mechanism,
A liquid ejecting device, wherein an opening is provided in the discharge side liquid chamber at a position above a position where the fluid flowing from the fluid introduction path flows into the discharge side liquid chamber. 3. The fluid introduction passage connects the discharge side liquid chamber of the discharge side pressure regulating valve and an upstream liquid supply passage upstream of the supply side liquid chamber of the liquid supply passage. The liquid ejecting apparatus according to any one of claims 1 to 6 . a liquid jet head having a nozzle surface on which nozzles for jetting liquid are opened;
a liquid supply path connected to the liquid inlet of the liquid ejecting head and supplying the liquid to the liquid ejecting head;
a liquid discharge path connected to a liquid outlet of the liquid jet head for discharging the liquid from the liquid jet head;
a supply-side pressure adjusting mechanism capable of adjusting the pressure inside the supply-side liquid chamber provided in the liquid supply path to a first pressure at which the gas-liquid interface formed in the nozzle is maintained;
a discharge-side liquid chamber provided in the liquid discharge path and connected to the liquid outlet, wherein the pressure in the discharge-side liquid chamber is lower than the pressure outside the discharge-side liquid chamber and the first pressure; Further, when the gas-liquid interface formed in the nozzle reaches a second pressure at which the gas-liquid interface is maintained, the valve can be opened to introduce fluid into the discharge-side liquid chamber and the discharge-side liquid chamber from outside the discharge-side liquid chamber. a discharge-side valve body that communicates with the fluid introduction path, and a discharge-side pressure adjustment that adjusts the pressure of the liquid supplied to the liquid jet head to a pressure that maintains the gas-liquid interface formed in the nozzle. a valve;
a flow mechanism connected to the discharge-side liquid chamber by a return flow path so as to be able to discharge the liquid in the liquid jet head to the liquid discharge path side through the discharge-side liquid chamber of the discharge-side pressure regulating valve; prepared,
The fluid introduction path connects the discharge-side liquid chamber of the discharge-side pressure regulating valve and an upstream liquid supply path upstream of the supply-side liquid chamber of the liquid supply path. Device. The liquid according to any one of claims 1 to 8 , wherein the fluid introduction path is configured to be capable of introducing gas into the discharge side liquid chamber of the discharge side pressure regulating valve. injector.

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