JP6390730B2 - Liquid ejection device - Google Patents

Description

  The present invention relates to a liquid ejection apparatus that ejects liquid onto a recording medium to form an image.

2. Description of the Related Art Conventionally, there is known an ink jet recording apparatus that has a liquid discharge head that discharges ink and performs printing by discharging ink from the liquid discharge head onto a recording medium. Patent Document 1 describes the internal structure of such a liquid discharge head.
In this case, ink chambers in which ink is stored are provided one above the other, and air discharge ports for discharging bubbles in the ink are provided at the top of each ink chamber. Each air discharge port is provided with a float member having a specific gravity smaller than that of the ink and a seal member positioned above the float member, and each air discharge port is connected to a pump that applies a negative pressure to the corresponding ink chamber. The The seal member allows gas to be discharged and prevents liquid from being discharged.
When discharging air bubbles in the ink, the air bubbles accumulated above the ink chamber are sucked out by the pump. The liquid level of the ink in each ink chamber rises, and the float member rises accordingly, and comes into contact with the seal member. Before the liquid level of the ink becomes higher than the air discharge port, the float member comes into contact with the seal member to block the ink from becoming higher, so that the ink is discharged from the air discharge port, Only air bubbles are discharged.

JP 2009-126044 A

In general, a liquid discharge head has a discharge surface in which a plurality of discharge ports for discharging ink are formed on a surface facing a recording medium. In general, such a liquid discharge head performs a purge operation, which is an operation for maintaining and recovering ink discharge characteristics. This purge operation is an operation for discharging ink from a plurality of ejection openings, and pressurizing the ink in each ink chamber to eject ink from the plurality of ejection openings, or to the ink in the plurality of ejection openings. On the other hand, it is applicable to discharge ink from a plurality of ejection openings by applying a suction pressure. However, when ink is discharged from a plurality of discharge ports by applying suction pressure to the ink in the plurality of discharge ports, air may be sucked from the air discharge port.
The conventional configuration is effective for discharging air bubbles in the ink from the air discharge port. However, during the purge operation, the ink chamber is depressurized by applying suction pressure to the ink in the plurality of discharge ports, and the seal is Since air may be sucked from the air discharge port through the member, there is a possibility that a negative pressure higher than the allowable pressure may be applied to the seal member at that time. As a result, the seal member is damaged, and when the bubbles are discharged next, not only the bubbles but also the ink may be discharged from the air discharge port.
An object of the present invention is to provide a liquid ejection device capable of reducing the possibility of damaging a seal member disposed at an air discharge port during a purge operation.

The liquid discharge apparatus includes a reservoir tank for storing liquid, an inflow port for allowing the liquid to flow into the reservoir tank, and a plurality of discharge ports for discharging the liquid stored in the reservoir tank. A liquid discharge head having an exhaust passage connected to the reservoir tank for discharging air accumulated in the reservoir tank, and connected to the exhaust passage to suck the gas in the exhaust passage. A liquid suction device comprising: a first suction device for suction; and a second suction device for sucking the liquid in the reservoir tank from the plurality of discharge ports,
In the exhaust flow path, a semipermeable membrane that allows passage of gas and blocks liquid is provided,
Of the exhaust flow path, a space constituted by a space closer to the reservoir tank than the semipermeable membrane and an internal space of the reservoir tank is defined as a first space on the semipermeable membrane side, the inlet, and the outlet. A check valve is provided at a location partitioned into the second space on the outlet side, and the check valve does not allow fluid to pass from the first space to the second space, and from the second space to the second space. The passage of fluid to the first space is allowed, and the first space is located above the discharge port.

  When the second suction device sucks the liquid in the reservoir tank, the check valve closes the flow path, so the pressure when sucking air in the exhaust flow path is upstream of the check valve in the liquid suction direction. It does not join the semipermeable membrane that is located. Thereby, damage to the semipermeable membrane can be prevented.

It is a front view which shows the internal structure of an inkjet recording device. It is the perspective view which looked at the liquid discharge head from the lower part. It is a block diagram which shows the periphery structure of a control part. (a), (b) is a figure which shows the structure of a liquid discharge head, (a) shows an initial state, (b) shows the state at the time of a suction purge operation, respectively. It is a figure which shows the state of the liquid discharge head at the time of exhaust purge. It is a flowchart which shows the operation | movement at the time of a suction purge operation | movement. It is a figure which shows the structure of the liquid discharge head which concerns on 2nd Embodiment, (a) shows an initial state, (b) shows an exhaust purge state, respectively. (a) is a diagram showing the state of the liquid ejection head after exhaust purge is completed, and (b) is a diagram showing the state of the liquid ejection head during the suction purge operation. It is a figure which shows the state of the liquid discharge head at the time of completion | finish of a suction purge operation | movement. It is a perspective view which shows a duckbill-like check valve. It is a figure which shows the modification of a liquid discharge head.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, upper and lower indicate directions along the vertical direction. Further, an ink jet recording apparatus is exemplified as the “liquid ejecting apparatus” according to the present invention, and the ink jet recording apparatus records an image by ejecting ink that is liquid onto a sheet that is a recording medium. Moreover, air is illustrated in the following embodiment as "gas" in this invention.

FIG. 1 is a diagram showing the overall configuration of the inkjet recording apparatus 1. The inkjet recording apparatus 1 has a rectangular parallelepiped casing 10, and a tray 11 for discharging the paper P is provided on the top plate of the casing 10. In the housing 10, the liquid discharge head 4 that discharges ink onto the paper P from the top to the bottom, the transport unit 5 that transports the paper P in the horizontal direction in FIG. A paper feeding unit 6 that supplies the unit 5 is disposed. A platen 3 is provided below the liquid discharge head 4 so as to face the liquid discharge head 4 and support the conveyed paper P in a horizontal plane in FIG.
A control unit 8 that controls the operation of each mechanism and electric circuit in the housing 10 is disposed at a position where the liquid ejection head 4 does not interfere with the inner upper portion of the housing 10. A tank 14 that stores ink to be supplied to the liquid ejection head 4 is disposed on the lower side inside the casing 10. The tank 14 and the liquid discharge head 4 are connected by a tube (not shown), and the ink in the tank 14 is supplied to the liquid discharge head 4. The liquid discharge head 4 is disposed above the tank 14, and a negative pressure corresponding to the water head pressure is applied to the ink in the liquid discharge head 4.

A terminal 13 to which a signal including an image recording job transmitted from an external personal computer is input is provided on the side surface of the housing 10. A signal input from the terminal 13 is input to the control unit 8. On the upper surface of the housing 10, an operation panel 12 for inputting information by a user is provided.
The transport unit 5 is a mechanism for transporting the paper P in FIG. 1 from left to right and upward toward the tray 11. In the following description, the direction in which the paper P is transported in the region immediately below the liquid discharge head 4 is referred to as the sub-scanning direction or the first direction (transport direction). An in-plane direction in which the sheet P is conveyed in the first direction in a direction orthogonal to the direction in which the sheet P is conveyed is defined as a main scanning direction or a second direction. In FIG. 1, the first direction is a horizontal direction from left to right, and the second direction is a direction orthogonal to the paper surface of the paper P.

The transport unit 5 includes first and second transport roller pairs 51 and 52 disposed on both sides of the liquid discharge head 4, and third to third transport rollers disposed downstream of the transport roller pair 52. A pair of five transport rollers 53, 54, and 55 and three guides 56, 57, and 58 through which the paper P passes are configured. Between the first transport roller pair 51 and the liquid ejection head 4, an end detection sensor SE1 that detects an end of the transported paper P is provided. The detection signal generated by the end detection sensor SE1 is transmitted to the control unit 8. When the leading edge of the conveyed paper P is detected by the edge detection sensor SE1, ink ejection from the liquid ejection head 4 to the paper P is started after a predetermined time has elapsed.
The sheet P to which the conveying force is applied by the first conveying roller pair 51 is conveyed in the horizontal plane while ink is ejected from the liquid ejection head 4.

The sheet P that has passed through the lower side of the liquid ejection head 4 is given conveyance force by the second conveyance roller pair 52 on the downstream side in the conveyance direction, and is positioned between the second conveyance roller pair 52 and the tray 11. The paper is fed to the tray 11 by the third to fifth transport roller pairs 53, 54, 55 and guides 56, 57, 58.
The paper feed unit 6 includes a paper feed tray 60 in which the paper P is stored, a paper feed roller 61, and a sixth and seventh transport roller pair 62 disposed between the paper feed roller 61 and the transport unit 5. , 63 and two guides 64, 65 through which the paper P passes. After feeding one sheet P out of the sheet feed tray 60, the sheet feed roller 61 takes out the next sheet P at a predetermined time interval, and guides 64, 65 and the sixth and seventh transport roller pairs 62. , 63 to transport the paper P to the upstream side of the transport unit 5 in the transport direction.

The liquid discharge head 4 is a rectangular parallelepiped line head extending in the main scanning direction (second direction), and a plurality of discharge surfaces 40 each having a plurality of discharge ports for discharging ink are formed on the lower surface thereof. Yes.
The sheet P on which an image is recorded by the liquid ejection head 4 is discharged to the tray 11 by the second to fifth transport roller pairs 52, 53, 54, 55 and the guides 56, 57, 58.
Below the platen 3, a plurality of liquid receiving members 70 arranged horizontally are provided so as to be movable up and down with respect to the platen 3. The liquid receiving member 70 is formed in a cap shape, and when printing is performed by ejecting ink onto the paper P, the liquid receiving member 70 is positioned below the conveyance path of the paper P so as not to interfere with the printing. Yes. The liquid receiving member 70 receives ink discharged or discharged from the liquid discharge head 4 in a state where the paper P is not conveyed to the platen 3. A waste liquid tube 71 is connected to the bottom surface of the liquid receiving member 70, and the waste liquid tube 71 is connected to the liquid suction pump P2. The ink discharged to the liquid receiving member 70 is sucked by the liquid suction pump P2.
When the paper P is not transported onto the platen 3, the liquid discharge head 4 is lowered, and the head element 41 that has passed through a through hole (not shown) formed in the platen 3 is aligned with the liquid receiving member 70, so that the liquid A purge operation that is a maintenance / recovery operation of the ink ejection characteristics of the ejection head 4 is performed. The purge operation is an operation of discharging ink from a plurality of discharge ports, and corresponds to discharge of ink by pressure reduction or pressurization, discharge by liquid discharge by discharge operation, and the like. In the following description, a suction purge operation in which ink is forcibly sucked from the discharge surface 40 by a pump while the liquid receiving member 70 covers the discharge surface 40 will be exemplified as the purge operation.

FIG. 2 is a perspective view of the liquid discharge head 4 as viewed from below. A plurality of head elements 41 protrude from the lower surface of the liquid discharge head 4, and the head elements 41 are arranged in a staggered manner in the second direction. The ejection surface 40 is the lower surface of the head element 41, and a plurality of ejection ports 42, which are nozzles for ejecting ink, are provided on the ejection surface 40 as described above. Each head element 41 is formed in the same structure in order to make the ink ejection characteristics uniform and reduce the manufacturing cost. The liquid ejection head 4 is formed by arranging six head elements 41 in a staggered manner in the second direction, but the number of head elements 41 is not limited to six.
The head element 41 is composed of a flow path unit formed by laminating a plurality of metal plates and an actuator unit joined to the upper surface of the flow path unit. When the actuator unit is energized, Ink is ejected. The lower surface of the metal plate located at the lowest position of the flow path unit constitutes the discharge surface 40, and the actuator unit is connected to the control unit 8. Such a configuration is known and will not be described in detail.

FIG. 3 is a block diagram showing a peripheral configuration of the control unit 8. The control unit 8 has one or a plurality of CPUs. The control unit 8 may be configured by combining one or more CPUs and one or more ASICs (Application Specific Integrated Circuits).
In addition to the motor group M that rotates the operation panel 12, the terminal 13, the first conveyance roller pair 51 to the seventh conveyance roller pair 63, the control unit 8 includes a ROM 83 that stores an operation program, and information temporarily. The RAM 84 serving as a work memory for recording the image, the liquid discharge head 4 and the end detection sensor SE1 are connected. The control unit 8 is connected to a liquid suction pump P2 connected to the liquid receiving member 70 and an air suction pump P1 for sucking air from the liquid discharge head 4 described later. The control unit 8 is connected to the pumps P1 and P2. Also drive.

(First embodiment)
4A and 4B are diagrams showing the configuration of the liquid discharge head 4, FIG. 4A shows the initial state, and FIG. 4B shows the state during the suction purge operation. For convenience of illustration, the platen 3 is not shown.
The liquid discharge head 4 is provided above the head element 41, the head element 41, a reservoir tank 9 for containing the ink supplied from the tank 14, and the ink supplied from the tank 14 to the reservoir. And an inlet 90 that leads into the tank 9. The air accumulated in the reservoir tank 9 is discharged through the exhaust passage 43. A semi-permeable membrane 44 that allows passage of air and blocks passage of ink is provided in the exhaust passage 43. The space constituted by the space closer to the reservoir tank 9 than the semipermeable membrane 44 and the internal space of the reservoir tank 9 is divided into a first space on the semipermeable membrane 44 side, the inlet 90 and the head by the check valve 2. It is divided into a second space on the element 41 side.
The air suction pump P1 and the exhaust flow path 43 constitute a “first suction device” of the present invention, and the liquid suction pump P2 and the liquid receiving member 70 constitute a “second suction device” of the present invention.

As shown in FIG. 2, six head elements 41 are arranged along the second direction below the liquid ejection head 4. In FIGS. 4A and 4B, for convenience of illustration, 1 Two head elements 41 are shown. In the present embodiment, the first space functions as the air reservoir 45, and the second space is constituted by a space closer to the reservoir tank 9 than the semipermeable membrane 44 and an internal space of the reservoir tank 9. Of these spaces, a space 95 excluding the air reservoir 45 is shown. The check valve 2 does not allow air to pass from the first space to the second space, and allows ink to pass from the second space to the first space. In other words, the check valve 2 does not allow air flow from the air reservoir 45 to the reservoir tank 9 but allows ink flow from the reservoir tank 9 to the air reservoir 45. The air reservoir 45 is located above the ink level in the reservoir tank 9 and the head element 41, and bubbles generated in the ink rise to enter the air reservoir 45.
The exhaust passage 43 is connected to the air suction pump P <b> 1 and sucks air in the air reservoir 45.

(Exhaust purge operation)
During the suction purge operation, the control unit 8 performs the operation shown in the flowchart of FIG.
The check valve 2 is open before the suction purge operation, that is, in the initial state where the pressure difference between the exhaust passage 43 and the air reservoir 45 is zero or close to zero. First, the liquid discharge head 4 is lowered and placed on the liquid receiving member 70 (step S1). Next, as shown in FIG. 5, the air suction pump P <b> 1 is operated to suck the air in the air pool chamber 45. This operation is called an exhaust purge operation (step S2). Since the check valve 2 is open and the air in the air reservoir 45 is sucked, the ink in the reservoir tank 9 is sucked into the air reservoir 45. Since the liquid receiving member 70 covers the discharge surface 40, it is difficult for air to enter the reservoir tank 9 from the discharge port 42. Further, the ink is prevented from flowing from the semipermeable membrane 44 to the exhaust passage 43 on the air suction pump P1 side by the semipermeable membrane 44.
The pressure (atmospheric pressure) in the exhaust passage 43 is about -3 kPa (kilopascal) before the start of the exhaust purge operation, and is about -10 kPa during the exhaust purge operation. The pressure in the air reservoir 45 is about −3 kPa before the start of the exhaust purge operation, but is assumed to be about −5 kPa during the exhaust purge operation. During the exhaust purge operation, the pressure in the exhaust passage 43 is about −10 kPa as described above. However, since a pressure loss due to the resistance of the semipermeable membrane 44 occurs, the pressure loss is assumed to be about 5 kPa, and −10 kPa +
Assuming that 5 kPa = -5 kPa, the pressure in the air reservoir 45 is assumed to be about -5 kPa during the exhaust purge operation.
After a predetermined time has elapsed from the start of the exhaust purge operation (step S3), the control unit 8 stops the operation of the air suction pump P1 (step S4). After the air suction pump P1 is stopped, the pressure in the exhaust passage 43 and the pressure in the air reservoir 45 are both about -3 kPa.

(Suction purge operation)
After the exhaust purge operation is stopped, the control unit 8 operates the liquid suction pump P2 to perform a suction purge operation for sucking the liquid in the reservoir tank 9 toward the liquid receiving member 70 (step S5). As described above, the exhaust purge operation is performed before the suction purge operation. If air remains in the air reservoir 45 during the suction purge operation, the liquid suction pump P2 sucks the ink in the reservoir tank 9. When doing so, there is a possibility that the air in the air reservoir 45 is taken into the discharge port 42. In this case, when ink is ejected from the ejection port 42 and an image is printed on the paper P after the suction purge operation, there is a risk of causing ink ejection failure. Therefore, during the suction purge operation, the exhaust gas purge operation is performed in advance to remove the air remaining in the air pool chamber 45.

Before the suction purge operation is started, as described above, the pressure in the exhaust passage 43 and the pressure in the air reservoir 45 are both about -3 kPa. The pressure in the reservoir tank 9 is also about -3 kPa. The pressure in the reservoir tank 9 corresponds to the water head pressure in the tank 14.
During the suction purge operation, the ink in the air pool chamber 45 is sucked with the suction of the ink by the liquid suction pump P2. When the air in the exhaust passage 43 is to be sucked with the suction operation, the check valve 2 is closed as shown in FIG. 4B (step S6). The operating pressure of the check valve 2 is assumed to be about 2 kPa, and the pressure in the exhaust passage 43 and the pressure in the air reservoir chamber 45 are both about -5 kPa, which is reduced by about 2 kPa from the start of the suction purge operation. . Further, the suction pressure by the liquid suction pump P2 is assumed to be about −50 kPa so that the ink is sufficiently discharged by the liquid suction pump P2. Accordingly, the pressure in the reservoir tank 9 is reduced to about −50 kPa. During the suction purge operation, the check valve 2 is closed, so that the air in the exhaust passage 43 is not sucked. Therefore, during the suction purge operation, the pressure at which the air in the exhaust passage 43 is sucked is not applied to the semipermeable membrane 44. Thereby, damage to the semipermeable membrane 44 is prevented.
When a predetermined time has elapsed from the start of the suction purge operation (step S7), the suction purge operation ends (step S8). As shown in FIG. 4A, the check valve 2 returns to the open state. That is, the pressure difference between the exhaust flow path 43 and the air reservoir 45 is returned to zero or close to zero. The internal pressure values of the exhaust passage 43, the air reservoir 45, and the reservoir tank 9 are merely examples, and are not limited to these values.

(Second embodiment)
FIGS. 7A and 7B are views showing the configuration of the liquid discharge head 4 according to the second embodiment. FIG. 7A shows the initial state before the exhaust purge operation, that is, FIG. ) Indicates the exhaust purge state. FIG. 8A shows a state after the exhaust purge is completed. In the liquid discharge head 4 according to the present embodiment, the auxiliary check valve 20 is provided in the exhaust passage 43 on the air suction pump P1 side than the semipermeable membrane 44. The auxiliary check valve 20 allows the air flow in the suction direction by the air suction pump P1, and blocks the air flow in the reverse direction. In the exhaust passage 43, a downstream chamber 46 is formed between the auxiliary check valve 20 and the check valve 2.
In the initial state shown in FIG. 7 (a), the auxiliary check valve 20 is closed and operates with a force similar to that of the check valve 2, for example, a force of about 2 kPa. The check valve 2 is opened in the initial state as described above. In the initial state, the pressures in the reservoir tank 9, the air reservoir 45, the downstream chamber 46, and the exhaust passage 43 are all about -3 kPa.
When the exhaust passage 43 is long, the atmospheric pressure in the exhaust passage 43 changes due to a change in the temperature around the exhaust passage 43 and the check valve 2 may be closed carelessly. Alternatively, a load may be applied to the semipermeable membrane 44 due to a change in atmospheric pressure in the exhaust passage 43. In the present embodiment, this possibility is prevented by providing the auxiliary check valve 20 on the downstream side of the semipermeable membrane 44 in the air suction direction.

(Exhaust purge operation)
As described above, prior to the suction purge operation, as shown in FIG. 7B, the exhaust purge operation is performed by the air suction pump P1. When the exhaust pressure exceeds the operating force of the auxiliary check valve 20, the auxiliary check valve 20 opens and ink flows into the air reservoir 45. The ink is prevented from flowing from the semipermeable membrane 44 to the air suction pump P1 side by the semipermeable membrane 44.
Since the operating pressure of the auxiliary check valve 20 is about 2 kPa, both the pressure in the air reservoir 45 and the pressure in the reservoir tank 9 are about −5 kPa, which is reduced by about 2 kPa from the initial state.
Further, as described above, since the pressure in the exhaust passage 43 is about −10 kPa during the exhaust purge operation, the pressure in the downstream chamber 46 is also about −10 kPa. Although there is a difference of about 5 kPa between the pressure in the air reservoir 45 and the pressure in the downstream chamber 46, the pressure loss due to the semipermeable membrane 44 is about −5 kPa, so the air suction pump P 1 sandwiching the semipermeable membrane 44 is interposed. The pressure is balanced between the upstream side and the downstream side in the air suction direction.

After a predetermined time has elapsed from the start of the exhaust purge operation, the control unit 8 stops the operation of the air suction pump P1. As shown in FIG. 8 (a), the auxiliary check valve 20 is closed. In the state where the exhaust purge operation is completed, the pressure in the exhaust passage 43 returns from about −10 kPa to about −3 kPa. Immediately after the auxiliary check valve 20 is closed, the pressure in the air reservoir 45 is about −5 kPa, which is the pressure in the exhaust passage 43 minus the operating pressure of the auxiliary check valve 20. The pressure is about −10 kPa, which is reduced pressure loss due to the semipermeable membrane 44. Since the check valve 2 is open, when the pressure in the air reservoir 45 becomes negative, the air reservoir 45 is filled with ink. Thereafter, the pressure in the downstream chamber 46 returns to about −3 kPa, and the pressure in the air pool chamber 45, the reservoir tank 9 and the exhaust passage 43 is also about −3 kPa.

(Suction purge operation)
After the exhaust purge operation is completed, the suction purge operation is performed. FIG. 8B is a diagram showing a state during the suction purge operation. The ink in the reservoir tank 9 is sucked by the liquid suction pump P2, and the ink in the air pool chamber 45 is sucked. When the suction pressure exceeds the operating force of the check valve 2, the check valve 2 is closed. Thereby, the space in the reservoir tank 9 on the downstream side of the ink suction from the check valve 2 is sealed. Since the pressure in the reservoir tank 9 is about −50 kPa, the air reservoir 45 and the downstream chamber 46 are closed because the check valve 2 is closed while the operating pressure of the check valve 2 is reduced from the start of the suction purge operation. Both are about -5kPa. Since the check valve 2 is closed, the pressure in the exhaust passage 43 is maintained at about -3 kPa.

After a predetermined time has elapsed from the start of the suction purge operation, the suction purge operation is stopped. The pressure in the reservoir tank 9 gradually returns from about −50 kPa to about −3 kPa, which is the water head pressure. Since the pressure in the air reservoir 45 is about −5 kPa, the check valve 2 is opened and ink flows into the air reservoir 45 as shown in FIG. Thereby, the pressure in the air pool chamber 45 approaches about −3 kPa which is the water head pressure. The pressure in the downstream chamber 46 and the exhaust passage 43 is also about −3 kPa. As a result, as shown in FIG. 7A, the check valve 2 is opened, and the auxiliary check valve 20 is closed.
In other words, in the liquid discharge head 4 provided with the auxiliary check valve 20, the check valve 2 is inadvertently closed due to a change in temperature or pressure around the exhaust passage 43 or to the semipermeable membrane 44. The check valve 2 can be appropriately opened and closed in accordance with the exhaust purge operation and the suction purge operation.

As described above, the check valve 2 opens in the initial state and closes by the suction purge operation. Various types of check valves 2 of this type are conceivable. An example thereof is a duckbill-shaped check valve 2 shown in FIG. This is provided with a valve body 21 having an outer shape that extends vertically and gradually spreads from the upper end portion toward the lower end portion, and an opening 22 penetrating vertically is formed in the central portion. The valve body 21 is made of an elastic material such as synthetic resin, particularly a material that is non-corrosive to ink, and is installed so that the upper end portion faces the semipermeable membrane 44 and the lower end portion faces the head element 41. During the suction purge operation, the valve body 21 is elastically deformed to close the opening 22.
Since the duckbill-shaped valve body 21 is a general-purpose product with a known configuration, it helps to reduce costs. If the valve body 21 is made of metal, the check valve 2 is immersed in the ink during the exhaust purge operation, which may adversely affect the ink. Therefore, the check valve 2 is made of a material that is non-corrosive to ink.

  In the above embodiment, the check valve 2 is provided in the vicinity of the horizontal liquid surface of the ink in the reservoir tank 9. However, instead of this, as shown in FIG. 11, a check valve 2 may be provided in the reservoir tank 9 obliquely below the horizontal liquid surface of the ink. That is, the check valve 2 has a space constituted by a space closer to the reservoir tank 9 than the semipermeable membrane 44 and an internal space of the reservoir tank 9 as a first space on the semipermeable membrane 44 side, an inlet 90 and What is necessary is just to be provided in the position divided into the 2nd space by the side of head element 41.

  The present invention is useful when used in a liquid ejection apparatus such as an ink jet recording apparatus that forms an image by ejecting a liquid such as ink onto a recording medium such as paper.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Check valve 4 Liquid discharge head 5 Transfer unit 8 Control part 9 Reservoir tank 20 Auxiliary check valve 41 Head element 43 Exhaust flow path 44 Semipermeable membrane 45 Air reservoir

Claims (5)

A tank for storing liquid, and a reservoir tank for storing liquid supplied from the tank;
An inlet for allowing the liquid supplied from the tank to flow into the reservoir tank;
A head element having a plurality of discharge ports for discharging the liquid stored in the reservoir tank;
An exhaust passage connected to the reservoir tank for exhausting air accumulated in the reservoir tank;
A gas suction device connected to the exhaust flow path for sucking the gas in the exhaust flow path;
A liquid suction device for sucking the liquid in the reservoir tank from the plurality of discharge ports;
A controller for controlling the operation of the gas suction device and the liquid suction device, and a liquid ejection device comprising:
In the exhaust flow path, a semipermeable membrane that allows passage of gas and blocks liquid is provided,
Of the exhaust flow path, a space constituted by a space closer to the reservoir tank than the semipermeable membrane and an internal space of the reservoir tank is defined as a first space on the semipermeable membrane side, the inlet, and the outlet. A check valve is provided at a location separated from the second space on the outlet side,
The check valve does not permit passage of fluid into the second space from the first space state, and are not to permit passage of fluid from said second space to said first space,
Wherein, when operating the liquid suction device, that controls so as to operate the gas suction device in front, a liquid ejecting apparatus. A tank for storing liquid, and a reservoir tank for storing liquid supplied from the tank;
An inlet for allowing the liquid supplied from the tank to flow into the reservoir tank;
A head element having a plurality of discharge ports for discharging the liquid stored in the reservoir tank;
An exhaust passage connected to the reservoir tank for exhausting air accumulated in the reservoir tank;
A liquid suction device for sucking the liquid in the reservoir tank from the plurality of discharge ports,
In the exhaust flow path, a semipermeable membrane that allows passage of gas and blocks liquid is provided,
Of the exhaust flow path, a space constituted by a space closer to the reservoir tank than the semipermeable membrane and an internal space of the reservoir tank is defined as a first space on the semipermeable membrane side, the inlet, and the outlet. A check valve is provided at a location separated from the second space on the outlet side,
The exhaust direction in the exhaust flow path and at a location downstream of the semipermeable membrane in the exhaust direction in which air flows in the exhaust flow path when the air accumulated in the reservoir tank is discharged. An auxiliary check valve is provided that allows a gas flow toward, and does not allow a gas flow toward the opposite direction to the exhaust direction;
The liquid ejection device, wherein the check valve does not allow fluid to pass from the first space to the second space but allows fluid to pass from the second space to the first space. A tank for storing liquid, and a reservoir tank for storing liquid supplied from the tank;
An inlet for allowing the liquid supplied from the tank to flow into the reservoir tank;
A head element having a plurality of discharge ports for discharging the liquid stored in the reservoir tank;
An exhaust passage connected to the reservoir tank for exhausting air accumulated in the reservoir tank;
A liquid suction device for sucking the liquid in the reservoir tank from the plurality of discharge ports,
In the exhaust flow path, a semipermeable membrane that allows passage of gas and blocks liquid is provided,
Of the exhaust flow path, a space constituted by a space closer to the reservoir tank than the semipermeable membrane and an internal space of the reservoir tank is defined as a first space on the semipermeable membrane side, the inlet, and the outlet. A check valve is provided at a location separated from the second space on the outlet side,
The first space is located above the ink level in the reservoir tank and below the semipermeable membrane,
The liquid ejection device, wherein the check valve does not allow fluid to pass from the first space to the second space but allows fluid to pass from the second space to the first space.   The liquid ejection device according to claim 2, wherein the auxiliary check valve is in a closed state when the pressure on the gas suction device side and the pressure on the semipermeable membrane side are in equilibrium.   5. The liquid ejection device according to claim 1, wherein the check valve is a duckbill valve formed of an elastic material that is non-corrosive to the liquid stored in the reservoir tank.

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