JP6501012B2 - Liquid injection apparatus and maintenance method for liquid injection apparatus - Google Patents

Description

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

  As an example of a liquid ejecting apparatus, there is an ink jet printer that performs printing by discharging ink from a nozzle provided in a recording head. Among such printers, there is a printer that attempts to suppress dot omission caused by air bubbles mixing in the nozzles by degassing the ink in the liquid storage chamber that stores the ink supplied to the recording head (for example, for example, , Patent Document 1).

JP, 2013-75371, A

  By the way, in the above-described printer, the sedimentation of the pigment component contained in the ink is suppressed by circulating the ink between the liquid storage chamber and the recording head when printing is not performed. By circulating the ink in this manner, it is also possible to expect the effect that bubbles mixed in the flow path can be collected in the liquid storage chamber. However, if the ink containing bubbles is recovered, the degassing degree of the ink in the liquid storage chamber is reduced, so the degassing of the ink must be performed each time the circulation is performed, and the degassing efficiency is deteriorated. There is a problem of

  Such a problem is not limited to a printer that performs printing by ejecting a pigment ink, and in a liquid ejecting apparatus in which bubbles grown in the liquid or bubbles mixed in the liquid may cause ejection failure of the liquid. It is generally common.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a liquid ejecting apparatus capable of reducing the mixture of air bubbles into a liquid to be jetted and the growth of air bubbles in the liquid. It is.

Hereinafter, the means for solving the above-mentioned subject and its operation effect are described.
A liquid ejecting apparatus that solves the above-described problems includes a plurality of nozzles capable of ejecting liquid, a common liquid chamber that supplies liquid to the plurality of nozzles, and a liquid contained in a liquid storage unit to the common liquid chamber. A liquid flow path for the liquid, a liquid flow portion capable of pressurizing liquid in the liquid flow path, and the liquid flow path provided between the liquid flow portion and the common liquid chamber and supplied to the common liquid chamber Pressure adjusting portion for adjusting the pressure of the liquid, a return flow path connecting the common liquid chamber and the liquid storage portion, an on-off valve closing the feedback flow path when the valve is closed, A control unit which causes the liquid in the common liquid chamber to flow toward the return flow path by opening the on-off valve while controlling the liquid flow portion to pressurize the liquid in the liquid flow path; Prepare.

In the liquid ejecting apparatus, a plurality of common liquid chambers are provided, and a plurality of branched liquids are branched corresponding to each of the plurality of common liquid chambers on the common liquid chamber side from the liquid flowing portion with respect to the liquid flow path A flow path is provided, and the pressure adjustment unit is provided in each of the plurality of branched liquid flow paths corresponding to the plurality of common liquid chambers, and the return flow path corresponds to each of the plurality of common liquid chambers. And a plurality of branched feedback flow channels that branch.

The liquid ejecting apparatus further includes a filter at a position between the liquid flowing portion and the liquid branch flow path in the liquid flow path.

The liquid ejecting apparatus further includes a degassing unit capable of degassing the liquid in the liquid flow path.

In the liquid ejecting apparatus, the degassing unit has a pressure reducing mechanism that decompresses the liquid in the liquid flow path for degassing, and the liquid flowing unit is directed from the degassing unit toward the common liquid chamber. Supply the liquid under pressure.

According to this configuration, when the pressure reducing mechanism reduces the pressure of the liquid, the gas contained in the liquid can be removed for degassing. In addition, by pressurizing the liquid whose pressure has been reduced by the liquid flowing portion, the liquid can be made to flow from the degassing portion toward the common liquid chamber.

In the liquid ejecting apparatus, the pressure adjusting unit includes a supply chamber in communication with the liquid storage portion side of the liquid flow passage, a pressure chamber in communication with the common liquid chamber side of the liquid flow passage, and the pressure chamber. A biasing member configured to bias the flexible portion in a direction in which the volume of the pressure chamber increases, and the flexible portion when the pressure in the pressure chamber becomes lower than the pressure outside the flexible portion And a valve body displaced in a direction to make the pressure chamber and the supply chamber communicate with each other according to the displacement of the pressure chamber.

A maintenance method of a liquid ejecting apparatus for solving the above-mentioned problems includes a plurality of nozzles capable of ejecting a liquid, a common liquid chamber for supplying the liquid to the plurality of nozzles, and a liquid contained in a liquid storage unit. Provided between a liquid flow path for supplying a liquid chamber, a liquid flow portion capable of pressurizing liquid in the liquid flow path, and the liquid flow path between the liquid flow portion and the common liquid chamber in the liquid flow path, The pressure control unit for adjusting the pressure of the liquid supplied to the common liquid chamber, the return flow path connecting the common liquid chamber and the liquid storage portion, and the valve closing state close the return flow path. A maintenance method of a liquid ejecting apparatus including an on-off valve, wherein the on-off valve is opened in a state where the liquid in the liquid flow path is pressurized by the liquid flowing portion, and the liquid in the common liquid chamber is opened. Flow toward the return flow channel.

In the liquid jet apparatus maintenance method for solving the above problems, the liquid jet apparatus may further include, in the return flow channel, a second liquid flow unit capable of depressurizing the liquid in the return flow channel, the liquid flow With the liquid in the passage pressurized, the on-off valve is opened to communicate the common liquid chamber with the return flow passage to reduce the pressure in the liquid in the common liquid chamber.

The maintenance method of the liquid ejecting apparatus for solving the above-mentioned subject is characterized in that when the liquid in the common liquid chamber is made to flow toward the return flow channel and collected in the liquid storage unit, the liquid storage unit is opened to the atmosphere. Do.

A maintenance method of a liquid ejecting apparatus for solving the above-mentioned problems causes the liquid in the common liquid chamber to flow toward the return flow path when the liquid is not ejected from the nozzle.

FIG. 1 is a schematic view showing the configuration of a liquid ejecting apparatus according to an embodiment. FIG. 2 is a block diagram showing an electrical configuration of the liquid ejecting apparatus according to an embodiment. The flowchart which shows the execution procedure of the 1st filling process. The flowchart which shows the execution procedure of 2nd filling processing. The flowchart which shows the execution procedure of pressurization cleaning processing.

  Hereinafter, embodiments of the liquid ejecting apparatus will be described with reference to the drawings. The liquid ejecting apparatus is, for example, an ink jet printer that performs recording (printing) by ejecting a pigment ink, which is an example of a liquid, onto a medium such as paper.

  As shown in FIG. 1, the liquid ejecting apparatus 11 includes a liquid storage unit 12 capable of containing liquid, a plurality of liquid ejecting units 13 for ejecting liquid, and a liquid ejecting unit 13 for liquid contained in the liquid storage unit 12. And a maintenance device 15 for performing maintenance of the liquid ejecting unit 13. The liquid storage unit 12 can be configured to be capable of injecting a liquid through an injection hole (not shown) in a state of being attached to the liquid ejection device 11 or the cartridge-like liquid storage unit 12 can be detachably attached to the liquid ejection device 11 It can also be configured to be attached.

  The liquid ejecting unit 13 has a plurality of nozzles 16 capable of ejecting a liquid, and a common liquid chamber 17 for supplying the liquid supplied from the liquid storage unit 12 through the liquid channel 14 to the plurality of nozzles 16. . The number of liquid jet units 13 and the number of nozzles 16 can be arbitrarily changed. As a mechanism for ejecting the liquid from the nozzle 16, for example, an actuator provided with a piezoelectric element that contracts when energized can be adopted. In this case, the liquid is ejected (discharged) as droplets from the nozzle 16 by changing the volume of the liquid chamber 16a provided between the common liquid chamber 17 and the nozzle 16 by contraction of the piezoelectric element.

  The liquid ejecting apparatus 11 includes a return flow passage 18 connecting the common liquid chamber 17 and the liquid storage unit 12, an open / close valve 19 closing the return flow passage 18 when the valve is closed, and a liquid from the common liquid chamber 17. And a circulation pump 20 for causing the liquid to flow toward the storage unit 12. When a plurality of liquid ejecting portions 13 are provided, the downstream side of the liquid flow path 14 connected to the common liquid chamber 17 and the upstream side of the return flow path 18 are branched into a plurality of portions depending on the number of common liquid chambers 17 .

  The liquid flow path 14 is provided with a degassing unit 21 capable of degassing the liquid in the liquid flow path 14. The degassing unit 21 may include, for example, a cylindrical hollow fiber membrane 22 that forms a part of the liquid flow channel 14 and a pressure reduction mechanism 25 that decompresses the liquid in the liquid flow channel 14 for degassing. it can. In this case, the pressure reducing mechanism 25 includes a pressure reducing chamber 23 that accommodates the hollow fiber membrane 22 and a vacuum pump 24 that reduces the pressure in the pressure reducing chamber 23. Then, when the vacuum pump 24 decompresses the decompression chamber 23, the space outside the hollow fiber membrane 22 is decompressed, and the gas dissolved in the liquid inside the hollow fiber membrane 22 is drawn to the outside of the hollow fiber membrane 22. Thus, the liquid inside the hollow fiber membrane 22 is degassed.

  A pressure adjusting unit 31 is provided between the degassing unit 21 and the liquid ejecting unit 13 in the liquid flow channel 14 to adjust the pressure of the liquid supplied to the liquid ejecting unit 13. The pressure adjustment unit 31 includes, for example, a pressure chamber 33 whose volume is changed by the bending displacement of the flexible portion 32 constituting the wall, and a supply chamber 35 in communication with the pressure chamber via the communication channel 34; The pressure member 33 includes a biasing member 36 that biases the flexible portion in a direction in which the volume of the pressure chamber 33 increases, and a valve body 37 capable of closing the communication passage 34. The supply chamber 35 can communicate with the degassing unit 21 through the liquid flow passage 14, and the pressure chamber 33 can communicate with the common liquid chamber 17 through the liquid flow passage 14.

It is to be noted that foreign matters such as air bubbles are likely to be accumulated in a portion where the flow passage cross-sectional area is expanded, such as the supply chamber 35 and the pressure chamber 33, or a portion having a complicated shape such as the biasing member 36. Therefore, in the present embodiment, the filters 38 and 39 are respectively provided at the inlet of the pressure adjusting unit 31 and the inside of the pressure adjusting unit 31 in order to capture foreign substances such as air bubbles. The number and arrangement of the filters 38 and 39 can be arbitrarily changed, and the installation of the filters 38 and 39 can be omitted.

  The liquid injection device 11 has an upstream end connected between the degassing unit 21 and the pressure adjustment unit 31 in the liquid flow passage 14, and a downstream between the on-off valve 19 and the common liquid chamber 17 in the return flow passage 18. It is preferable to provide a bypass channel 41 to which the end is connected. Further, switching of the flow path of the liquid from the degassing unit 21 toward the common liquid chamber 17 can be switched between the liquid flow path 14 and the bypass flow path 41 to the connection portion between the bypass flow path 41 and the liquid flow path 14 Preferably, a valve 42 is provided.

  The switching valve 42 has, for example, an upstream side of a connection portion between the bypass flow path 41 and the liquid flow path 14 with the bypass flow path 41 and a downstream side with a connection portion with the bypass flow path 41 in the liquid flow path 14. The three flow paths can be three-way valves provided with three valve bodies that can be closed individually.

  It is preferable to provide a reservoir 43 for temporarily storing the liquid degassed by the degassing unit 21 between the degassing unit 21 and the switching valve 42 in the liquid flow path 14. Further, a pressure pump 45 is provided between the degassing unit 21 and the liquid storage unit 12 in the liquid flow channel 14 to supply the liquid from the degassing unit 21 to the liquid jet unit 13 in a pressurized state. Is preferred.

  The pressurizing pump 45 can function as a liquid flow unit that causes the liquid in the liquid flow channel 14 to flow. That is, since the liquid in the liquid flow path 14 is depressurized in the degassing unit 21, the liquid ejecting unit can be stored by storing the degassed liquid in the storage unit 43 in a pressurized state by the pressurizing pump 45. It becomes possible to efficiently supply the liquid toward 13.

  In the liquid flow channel 14, while the flow of the liquid from the degassing unit 21 to the storage unit 43 is allowed between the degassing unit 21 and the storage unit 43, the flow from the storage unit 43 to the degassing unit 21 is It is preferable to provide a one-way valve 46 which regulates the flow of the liquid. In this way, it is possible to suppress the backflow of the liquid from the reservoir 43 which has been brought into the positive pressure state by pressurization to the deaeration part 21 which has been brought into the negative pressure state by depressurization.

  Moreover, while using the accommodation bag which has flexibility as the storage part 43, the storage part 43 which consists of such an accommodation bag is accommodated in the pressurization chamber 47, and the gas which the vacuum pump 24 drew for pressure reduction is used. It may be configured to be introduced into the pressurizing chamber 47 through the gas channel 61. In this case, by driving the vacuum pump 24 to introduce the gas into the pressurizing chamber 47, it is possible to pressurize the liquid inside the container via the storage bag.

  When adopting this configuration, if the three-way valves 62 and 63 are disposed on the upstream side and the downstream side of the vacuum pump 24 in the gas flow path 61, the timing for depressurizing the decompression chamber 23 and the pressurizing chamber The timing to pressurize 47 can be set arbitrarily.

  That is, when simultaneously depressurizing the depressurizing chamber 23 and pressurizing the pressurizing chamber 47, the valves 62a and 63a communicating with the outside of the three-way valves 62 and 63 are closed to drive the vacuum pump 24. Then, the gas in the decompression chamber 23 may be introduced into the pressurization chamber 47. Further, when the pressure in the pressure reducing chamber 23 is independently reduced, the valve 62a is closed and the valve 63a is opened to drive the vacuum pump 24 so that the gas drawn from the pressure reducing chamber 23 is discharged to the outside. Just do it. Further, when pressurizing the pressurizing chamber 47 alone, the external gas is taken into the gas flow path 61 by opening the valve 62a and closing the valve 63a to drive the vacuum pump 24. It may be introduced into the pressure chamber 47.

The liquid flow path 14 is provided between the degassing unit 21 and the liquid storage unit 12 with a foreign matter capture unit for capturing foreign matters such as air bubbles and dust mixed in the liquid, solidified matter of the solute component dissolved in the liquid. Is preferred. The foreign matter capture unit may be, for example, a filter 48 for filtering the liquid, or an air trap 49 for capturing air bubbles mixed in the liquid, or may be a foreign matter highly likely to be mixed. These may be used in combination.

  When the air trap 49 has the liquid storage portion 49a and the gas storage portion 49b in communication with each other to separate gas and liquid, the liquid is made to flow from the liquid storage portion 12 toward the liquid storage portion 49a. Preferably, a discharge pump 50 is provided.

  The maintenance device 15 includes a cap 51 forming a closed space in which the nozzle 16 provided in the liquid ejecting unit 13 is opened, a suction mechanism 52, and a wiper unit 53. The suction mechanism 52 includes a waste liquid tank 54, a discharge flow path 55 connecting the waste liquid tank 54 and the cap 51, and a pressure reduction pump 56 disposed at an intermediate position of the discharge flow path 55. Further, the cap 51 is provided with an air release valve 57 for releasing the closed space to the atmosphere.

  The cap 51 performs capping for forming a closed space by, for example, coming into contact with the opening surface 13 a where the nozzle 16 opens in the liquid ejecting unit 13. The capping can be performed by moving the liquid ejecting unit 13 in the direction approaching the cap 51, or can be performed by moving the cap 51 in the direction approaching the liquid ejecting unit 13. The object with which the cap 51 contacts during capping is not limited to the opening surface 13a. For example, the nozzle 16 can contact the holding member or the like that holds the side surface of the liquid ejecting unit 13 or the liquid ejecting unit 13 with the cap 51. It is also possible to form a closed space that opens.

  Then, when the decompression pump 56 is driven in a capping state, suction pressure is applied to the closed space, and suction cleaning is performed in which the liquid is sucked and discharged from the common liquid chamber 17 through the nozzle 16.

  That is, when the pressure reducing pump 56 is driven and the closed space becomes negative pressure, the liquid is discharged from the nozzle 16 and the liquid in the pressure chamber 33 flows into the common liquid chamber 17 to reduce the pressure in the pressure chamber 33. . Then, the flexible portion 32 constituting the wall of the pressure chamber 33 is bent and displaced in the direction to reduce the volume of the pressure chamber 33. Then, in accordance with the displacement of the flexible portion 32, the valve body 37 is displaced in the direction (left direction in FIG. 1) which causes the pressure chamber 33 and the supply chamber 35 to communicate with each other.

  When the pressure chamber 33 and the supply chamber 35 communicate with each other (the state of the pressure adjustment unit 31 on the right side in FIG. 1) due to the displacement of the valve body 37, liquid flows from the supply chamber 35 under pressure into the pressure chamber 33. To flow. Thereafter, when the driving of the pressure reducing pump 56 is stopped, the liquid does not flow out from the nozzle 16, so the flexible portion 32 is displaced in the direction to expand the volume of the pressure chamber 33 as the pressure in the pressure chamber 33 rises. At the same time, the valve body 37 returns to its original position and closes the communication passage 34. As described above, in the pressure adjusting unit 31, while suction from the nozzle 16 side is being performed, the liquid is supplied to the common liquid chamber 17 through the liquid flow channel 14.

  When releasing the capping after such suction cleaning, it is preferable to release the cap 51 from the liquid ejecting unit 13 after opening the closed space by opening the air release valve 57 to open the closed space.

  The wiper unit 53 includes a wiper 58 that wipes the opening surface 13a, and a moving body 59 that holds and moves the wiper 58. Then, the moving body 59 moves along the opening surface 13 a in a state where the end of the wiper 58 is in contact with the opening surface 13 a, whereby wiping for wiping the opening surface 13 a with the wiper 58 is performed. The wiping can also be performed by moving the liquid ejecting unit 13 in contact with the wiper 58.

  In addition, as maintenance of the liquid ejecting unit 13, flushing is performed to eject the liquid from the liquid ejecting unit 13 toward the cap 51 to discharge the liquid in the nozzle 16. The flushing may be performed to prevent or eliminate clogging of the nozzle 16 between printings or the like, or may be performed to adjust the meniscus of the liquid formed in the nozzle 16 after wiping, for example. Sometimes.

  Further, as shown in FIG. 2, the liquid ejecting apparatus 11 includes a liquid ejecting unit 13, a discharge pump 50, a pressure pump 45, a vacuum pump 24, a circulation pump 20, an on-off valve 19, a switching valve 42, a moving body 59, and the atmosphere. The control unit 100 controls components of the liquid injection device 11, such as the open valve 57 and the pressure reducing pump 56. The control unit 100 can provide a plurality of units for individually controlling the constituent elements, or can provide a unit for comprehensively controlling the plurality of constituent elements.

  In the liquid ejecting apparatus 11, under the control of the control unit 100, the on / off valve 19 and the atmosphere open valve 57 are closed and the switching valve 42 switches the liquid flow path to the liquid flow path 14 as the normal state. Do. Further, in the normal state, the control unit 100 caps the liquid ejecting unit 13 with the cap 51 to suppress the drying of the nozzle 16.

  When the liquid ejecting apparatus 11 is activated, the discharge pump 50 and the pressure pump 45 are drive-controlled by the control unit 100 so that the inside of the storage unit 43 is maintained at a predetermined positive pressure (pressurized state). Thus, in the normal state, the storage section 43, the supply chamber 35, and the liquid flow path 14 between the storage section 43 and the supply chamber 35 are held in a predetermined pressurized state. Further, the control unit 100 controls the vacuum pump 24 and the three-way valves 62 and 63 in accordance with the driving of the pressure pump 45 to decompress the decompression chamber 23, and sends the degassed liquid to the storage unit 43. To be able to

  Note that even if the liquid in the supply chamber 35 is in a pressurized state, the valve body 37 in the pressure adjustment unit 31 blocks the communication flow path 34 by the biasing force of the biasing member 36 (pressure on the left side in FIG. While the state of the adjustment unit 31 is maintained, the liquid does not flow from the supply chamber 35 to the pressure chamber 33.

Next, operations of the liquid ejecting apparatus 11 and various processes performed by the control unit 100 will be described.
First, when the use of the liquid ejecting apparatus 11 is started, etc., the first filling process performed to fill the liquid of the liquid flow path 14 into the common liquid chamber 17 and the common liquid following the first filling process The second filling process performed to fill the nozzle 16 with the liquid in the chamber 17 will be described. The first filling process and the second filling process are started from the above-described normal state. In this normal state, the air release valve 57 of the cap 51 is in a closed state.

The first filling process is performed by the control unit 100 executing the process shown in FIG.
As shown in FIG. 3, in step S11, the control unit 100 changes the on-off valve 19 from the closed state, which is the normal state, to the open state.

  Next, in step S12, the control unit 100 starts driving of the circulation pump 20. Then, as a result that the liquid in the common liquid chamber 17 flows toward the liquid storage unit 12 through the return flow channel 18, the liquid in the pressure chamber 33 is supplied to the common liquid chamber 17, and the pressure chamber 33 is depressurized. Then, the flexible portion 32 constituting the wall of the pressure chamber 33 is bent and displaced in the direction to reduce the volume of the pressure chamber 33. Then, in accordance with the displacement of the flexible portion 32, the valve body 37 is displaced in the direction (left direction in FIG. 1) which causes the pressure chamber 33 and the supply chamber 35 to communicate with each other.

  When the pressure chamber 33 and the supply chamber 35 communicate with each other (the state of the pressure adjustment unit 31 on the right side in FIG. 1) due to the displacement of the valve body 37, liquid flows from the supply chamber 35 under pressure into the pressure chamber 33. To flow. Then, with the drive of the circulation pump 20, the liquid flows in the order of the pressure chamber 33, the common liquid chamber 17, and the return flow path 18. At this time, as shown by solid arrows in FIG. 1, the liquid is pressurized and supplied from the reservoir 43 to the supply chamber 35 through the liquid channel 14, and the pressurizing pump 45 and the discharge pump are supplied to the reservoir 43. The liquid is replenished from the liquid storage unit 12 by the drive of 50.

  Subsequently, at step S13, the control unit 100 stops the driving of the circulation pump 20. Then, since the liquid does not flow out from the common liquid chamber 17 toward the return flow path 18, the flexible portion 32 is displaced in the direction to expand the volume of the pressure chamber 33 as the pressure in the pressure chamber 33 rises. At the same time, the valve body 37 returns to its original position and closes the communication passage 34.

  Then, when the control unit 100 returns the open / close valve 19 from the open state to the closed state, which is the normal state, in step S14, the first filling process ends. Thereby, the filling of the common liquid chamber 17 with the liquid is completed.

  In the case where the filters 38 and 39 are provided in the liquid flow path 14, for example, the pressure loss in the flow path is large, so that the liquid is less likely to flow toward the pressure chamber 33 even if the liquid is pressurized and supplied. There is. Therefore, the switching valve 42 is a three-way valve having a valve 42a disposed in the liquid flow path 14 downstream of the connection portion with the bypass flow path 41 and a valve 42b disposed in the bypass flow path 41, step S12. The valve 42a may be opened after the valve 42a is closed for a certain period of time between step S13 and step S13. In this case, the negative pressure of the pressure chamber 33 extends to the valve 42a while the valve 42a is closed, so the pressurized fluid flows in a stroke at a time in the region where the negative pressure is obtained as the valve 42a is opened. Liquid can be filled efficiently.

Next, the second filling process will be described with reference to FIG.
The second filling process is performed as a preparatory operation for filling the liquid in the common liquid chamber 17 into the nozzle 16 so as to be in a printable state after filling the liquid into the common liquid chamber 17 by the first filling process.

  As shown in FIG. 4, in step S21, the control unit 100 starts the driving of the pressure reducing pump 56. Then, the closed space formed by the capping is depressurized, and the liquid is sucked through the nozzle 16 and flows out into the cap 51.

Next, in step S22, the control unit 100 stops the driving of the pressure reducing pump 56.
In step S23, the control unit 100 changes the atmosphere open valve 57 from the closed state to the open state. As a result, the closed space is opened to the atmosphere, and the outflow of the liquid from the nozzle 16 is stopped. At this time, the nozzle 16 is filled with a liquid.

  Next, in step S24, the control unit 100 starts the driving of the pressure reducing pump 56 again. Thereby, the liquid accumulated in the cap 51 is discharged to the waste liquid tank 54 through the discharge flow channel 55. When the discharge of the liquid in the cap 51 is completed, the control unit 100 stops the driving of the pressure reducing pump 56 in step S25.

  Subsequently, at step S26, the control unit 100 releases the capping. Note that the release of capping in step S26 can also be performed between step S23 and step S24. In this case, the liquid accumulated in the cap 51 is discharged while the capping is released.

  In step S27, the control unit 100 moves the movable body 59 to execute wiping. As a result, droplets and the like that are discharged from the nozzle 16 by suction and adhere to the opening surface 13a are removed.

  Then, while the control unit 100 executes flushing to adjust the meniscus of the nozzles 16 in step S28, and the control unit 100 performs capping in step S29, the second filling process is completed. In the case where printing is immediately started after execution of the second filling process, capping in step S29 may not be performed.

  As described above, when the liquid is filled up to the nozzle 16 by the first filling process and the second filling process, the liquid ejecting apparatus 11 becomes ready to perform printing. The series of operations performed in the second filling process is the same as the operation in suction cleaning which is a maintenance operation for discharging foreign substances such as air bubbles through the nozzles 16.

  However, in the suction cleaning, the driving time of the pressure reducing pump 56 is set so that the liquid necessary for discharging the foreign matter is discharged from the nozzle 16, while in the second filling process, the liquid is discharged to the nozzle 16. The amount of liquid necessary for filling may flow. Therefore, the driving time of the decompression pump 56 in the second filling process may be generally shorter than that in the suction cleaning.

Then, when the liquid ejecting apparatus 11 performs printing, the control unit 100 releases the capping, and the liquid ejecting unit 13 ejects the liquid to the medium.
When the liquid flows out from the nozzle 16 and the liquid in the common liquid chamber 17 decreases with the injection of the liquid, the liquid flows from the pressure chamber 33 into the common liquid chamber 17 and the pressure in the pressure chamber 33 decreases. . That is, when the liquid flows out from the nozzle 16, the liquid in the pressure chamber 33 is supplied to the common liquid chamber 17, thereby reducing the pressure in the pressure chamber 33. Then, the flexible portion 32 is bent and displaced in the direction to reduce the volume of the pressure chamber 33. Then, when the pressure in the pressure chamber 33 becomes lower than the pressure on the outside of the flexible portion 32, the valve body 37 causes the pressure chamber 33 and the supply chamber 35 to communicate with each other according to the displacement of the flexible portion 32. Displace.

  When the pressure chamber 33 and the supply chamber 35 communicate with each other due to the displacement of the valve body 37, the liquid flows from the supply chamber 35 in a pressurized state into the pressure chamber 33. At this time, as shown by solid arrows in FIG. 1, the pressurizing pump 45 supplies the liquid from the degassing unit 21 toward the supply chamber 35 of the pressure adjusting unit 31 in a pressurized state, and the discharge pump 50 The liquid is supplied from the liquid storage unit 12 to the liquid storage unit 49a.

  Then, when the flexible portion 32 is displaced in the direction to expand the volume of the pressure chamber 33 with the inflow of the liquid, the valve body 37 returns to the original position and closes the communication flow path 34. As described above, when the liquid in the pressure chamber 33 is consumed, the liquid is promptly replenished from the supply chamber 35 in the pressurized state, and when the liquid consumption is not performed, the valve body 37 By closing the valve, a rise in fluid pressure from the pressure chamber 33 to the nozzle 16 is suppressed.

  In addition, when pressurization and depressurization of the liquid are repeated in the liquid chamber 16a in order to eject the liquid from the nozzle 16, the gas dissolved in the liquid appears as bubbles, and the pressure accompanying the driving of the piezoelectric element The change may not be sufficiently transmitted to the nozzle 16, which may cause droplet ejection failure. In addition, when the liquid is not jetted, the liquid does not flow in the liquid jet device 11, so when the liquid is a solution containing a component having a settling property such as a pigment, the pigment etc. precipitates and the liquid concentration A difference may occur.

  Therefore, when the liquid ejecting unit 13 does not eject the liquid, the liquid in the common liquid chamber 17 is returned to the liquid storage unit 12 through the return flow path 18, so that between the common liquid chamber 17 and the liquid storage unit 12. A circulation process is performed to circulate the liquid.

  Similar to the first filling process, the circulation process is performed by driving the circulation pump 20 after the control unit 100 opens the on-off valve 19. That is, when the circulation pump 20 is driven, the liquid in the common liquid chamber 17 flows toward the liquid storage portion 12 through the return flow path 18 as shown by the dotted arrow in FIG. The valve body 37 brings the supply chamber 35 and the pressure chamber 33 into communication by the pressure reduction of the chamber 33.

  Then, the liquid is supplied from the storage portion 43 to the supply chamber 35 through the liquid flow path 14, and the liquid in the liquid storage portion 12 is supplied to the storage portion 43 by the discharge pump 50 and the pressurizing pump 45. Thus, the liquid circulates between the liquid storage portion 12 and the common liquid chamber 17. Then, stirring of the pigment and the like is performed by the flow of the liquid, and foreign substances such as air bubbles and the like in the common liquid chamber 17 and the like are collected in the liquid storage unit 12. When air bubbles are collected in the liquid storage unit 12 by circulating the liquid in this manner, the liquid storage unit 12 is opened to the atmosphere, and the collected air bubbles are prompted to float on the liquid surface and be defoamed. It is good.

  When the liquid ejecting apparatus 11 performs circulation processing, the pressure in the common liquid chamber 17 may fluctuate with the flow of the liquid. When such pressure fluctuations reach the nozzle 16, the meniscus of the liquid formed on the nozzle 16 may be broken and the liquid may leak from the nozzle 16. Therefore, it is preferable to cap the liquid jet unit 13 with the cap 51 during the circulation process. In this case, the atmosphere open valve 57 of the cap 51 is preferably closed.

  Further, when the circulation pump 20 is driven to flow the liquid in the circulation process, the pressure in the common liquid chamber 17 may be a negative pressure lower than the atmospheric pressure. When this negative pressure is applied to the nozzle 16, the meniscus of the liquid formed on the nozzle 16 may be broken and air may be drawn from the nozzle 16. Therefore, it is preferable to drive the circulation pump 20 to such an extent that air is not drawn from the nozzle 16 in the circulation process. For example, it is preferable to drive the circulation pump 20 so that the pressure acting on the meniscus formed in the nozzle 16 by the fluid flow is lower than the pressure resistance of the meniscus.

Next, a pressure cleaning process, which is one of the maintenance operations for discharging the liquid from the liquid ejecting unit 13, will be described with reference to FIG.
As shown in FIG. 5, in step S <b> 31, the control unit 100 cancels capping of the liquid ejecting unit 13. When the capping is released, the cap 51 is disposed at a position facing the opening of the nozzle 16 (for example, a position below the opening surface 13a in the vertical direction) as shown in FIG.

  Next, in step S32, the control unit 100 closes the valve 42a of the switching valve 42 and opens the valve 42b to connect the fluid communication path of the storage unit 43 to the pressure adjustment unit 31 from the fluid flow channel 14 It switches to the bypass channel 41.

  Subsequently, in step S33, the control unit 100 drives the vacuum pump 24 or the like to start additional pressurization of the storage unit 43. The pressurization of the reservoir 43 can also be performed by driving the pressure pump 45 instead of or in addition to the driving of the vacuum pump 24.

  As a result, the liquid stored in the storage section 43 is pressurized and supplied to the common liquid chamber 17 through the bypass flow path 41 as indicated by a two-dot chain line in FIG. Then, the liquid in the common liquid chamber 17 flows out of the nozzle 16 and is received by the cap 51. As a result, air bubbles in the common liquid chamber 17 or the liquid chamber 16a, or a liquid that has thickened due to evaporation of the solvent component, etc. are discharged through the nozzle 16 together with the liquid, which is a foreign matter that causes ejection failure.

  When a sufficient amount of liquid for discharging the foreign matter is discharged from the nozzle 16, the control unit 100 stops the driving of the vacuum pump 24 or the like in step S34 to stop additional pressurization of the storage unit 43. .

  Further, in step S35, the control unit 100 opens the valve 42a of the switching valve 42 and closes the valve 42b to connect the flow passage in communication with the storage unit 43 from the bypass flow passage 41 to the pressure adjustment unit 31. It switches to the flow path 14 and returns to a normal state.

  Next, at step S36, the control unit 100 starts driving the pressure reducing pump 56. Thereby, the liquid accumulated in the cap 51 is discharged to the waste liquid tank 54 through the discharge flow channel 55. When the discharge of the liquid in the cap 51 is completed, the control unit 100 stops the driving of the pressure reducing pump 56 in step S37.

  Thereafter, in step S38, the control unit 100 moves the movable body 59 to execute wiping. As a result, the droplets and the like attached to the opening surface 13 a are removed along with the discharge of the liquid from the nozzle 16.

  Then, in step S39, the control unit 100 executes flushing to adjust the meniscus of the nozzle 16, and in step S40, the control unit 100 executes capping to complete the pressure cleaning process. In the case where printing is performed immediately after execution of the pressure cleaning, capping in step S40 may not be performed.

Next, the operation of the liquid ejecting apparatus 11 will be described.
When the liquid ejecting apparatus 11 ejects the liquid from the nozzle 16, the on-off valve 19 is closed to suppress the flow of the liquid from the common liquid chamber 17 to the return flow path 18, and the switching valve 42 is a flow path of the liquid Is switched to the liquid flow channel 14, the liquid is supplied to the pressure adjustment unit 31 through the liquid flow channel 14. Therefore, the liquid can be rapidly supplied from the pressure adjusting unit 31 to the common liquid chamber 17 with the consumption of the liquid while maintaining the back pressure of the nozzle 16 at a pressure suitable for the ejection of the liquid by the pressure adjusting unit 31 .

  On the other hand, when performing pressure cleaning, which is maintenance for causing the liquid to flow out of the nozzle 16, the on-off valve 19 is closed and the switching valve 42 switches the flow path of the liquid to the bypass flow path 41. The liquid is supplied to the common liquid chamber 17 through the bypass channel 41. That is, by sending the liquid from the storage unit 43 to the common liquid chamber 17 without passing through the pressure adjusting unit 31, the pressurized liquid is vigorously discharged from the nozzle 16 and the foreign matter is discharged from the liquid ejecting unit 13. Becomes possible.

In the pressure cleaning, the liquid flows into the common liquid chamber 17 through a part of the return flow channel 18 located between the bypass flow channel 41 and the common liquid chamber 17. Therefore, a foreign matter capture unit such as the filter 60 is provided in the feedback flow passage 18 located between the bypass flow passage 41 and the common liquid chamber 17 so that foreign matter flows into the common liquid chamber 17 as the pressure cleaning is performed. It is preferable to suppress.

  In addition, since the liquid ejecting apparatus 11 includes the return flow path 18, the liquid in the common liquid chamber 17 is obtained by causing the liquid in the return flow path 18 to flow toward the liquid storage portion 12 with the on-off valve 19 opened. It is collected in the liquid storage unit 12. As a result, it is possible to collect foreign substances such as bubbles accumulated in the common liquid chamber 17 or the like in the liquid storage unit 12 and to suppress the mixture of air bubbles in the liquid chamber 16 a and the nozzle 16.

  Further, by opening the on-off valve 19 and driving the circulation pump 20, the discharge pump 50 and the pressure pump 45, the common liquid chamber 17, the return flow path 18, the liquid storage portion 12 and the liquid flow path 14 are ordered in this order. When the liquid is circulated, the liquid in the flow path is agitated. As a result, even when the liquid contains a settling component such as a pigment, it is possible to suppress the change in concentration of the liquid. That is, since it is possible to suppress the occurrence of the ejection failure of the nozzle 16 and the deterioration of the printing quality without causing the liquid containing the foreign matter or the liquid having a changed concentration to flow out of the nozzle 16 and discarding it, it is consumed for maintenance. Amount of liquid can be reduced.

  Even if the liquid containing air bubbles is collected in the liquid storage unit 12, the liquid supplied from the liquid storage unit 12 toward the common liquid chamber 17 may be the liquid flow channel 14 or the bypass flow channel 41. The air is deaerated in the deaerator 21 regardless of the Thereby, generation | occurrence | production of the bubble in the flow path from the degassing part 21 to the nozzle 16 and the pressure adjustment part 31 is suppressed.

According to the above embodiment, the following effects can be obtained.
(1) Allowing the liquid contained in the common liquid chamber 17 or the liquid flow path 14 to be collected in the liquid containing portion 12 by causing the liquid in the common liquid chamber 17 to flow to the liquid containing portion 12 through the return flow path 18 it can. Further, in the liquid flow path 14 for supplying the liquid to the common liquid chamber 17, the degassing unit 21 degasses the liquid, so that the degassed liquid can be jetted from the nozzle 16. That is, the degassing in the liquid flow path 14 reduces the mixing of air bubbles into the liquid to be jetted and the growth of air bubbles in the liquid compared to the case of degassing the liquid in the liquid storage unit 12. can do.

  (2) The liquid in the common liquid chamber 17 is stored without passing through the degassing unit 21 by causing the liquid in the return flow channel 18 to flow toward the liquid storage unit 12 with the on-off valve 19 open. It can be collected in section 12. As described above, by suppressing the mixture of the deaerated liquid and the liquid containing bubbles, the liquid to be jetted can be deaerated efficiently.

  (3) When the liquid is jetted from the nozzle 16, the liquid adjusted to an appropriate pressure by the pressure adjusting unit 31 can be supplied to the nozzle 16 by supplying the liquid to the pressure adjusting unit 31 through the liquid channel 14. . On the other hand, when performing maintenance, by supplying the liquid to the common liquid chamber 17 without passing through the liquid adjusting unit through the bypass flow path 41, it is possible to vigorously flow out the liquid whose pressure is not adjusted from the nozzle 16.

  (4) When the liquid flows out from the nozzle 16, the liquid in the pressure chamber 33 is supplied to the common liquid chamber 17 so that the pressure in the pressure chamber 33 is reduced, and the flexible portion 32 has the volume of the pressure chamber 33. Flexure displacement in the direction to decrease. Further, in accordance with the displacement of the flexible portion 32, the valve body 37 causes the pressure chamber 33 and the supply chamber 35 to communicate with each other. Then, since the deaerated liquid is supplied to the supply chamber 35 in a pressurized state by the liquid flowing portion, when the pressure chamber 33 communicates with the supply chamber 35, the liquid from the supply chamber 35 to the pressure chamber 33 is rapidly Flow into When the pressure in the pressure chamber 33 returns to the original state due to the inflow of liquid, the inflow of liquid from the supply chamber 35 to the pressure chamber 33 is stopped by the biasing force of the biasing member 36. On the other hand, when the liquid does not flow out from the nozzle 16, the pressure in the pressure chamber 33 does not decrease, and the pressurized liquid does not flow into the common liquid chamber 17 through the pressure chamber 33. The meniscus of the formed liquid is not destroyed by pressurization. That is, the pressure adjustment unit 31 can appropriately adjust the pressure of the common liquid chamber 17 according to the outflow of the liquid from the nozzle 16.

(5) In the middle of the liquid flow path 14 from the liquid storage unit 12 to the degassing unit 21, the filter 48 or the air trap 49 which is the foreign matter capturing unit captures foreign matter mixed in the liquid, to the degassing unit 21. Contamination of foreign substances can be suppressed. As a result, clogging of the hollow fiber membrane 22 is suppressed, so that it is possible to suppress a decrease in the degassing performance of the degassing unit 21.

  (6) The decompression mechanism 25 decompresses the liquid, whereby the gas contained in the liquid can be removed for degassing. In addition, the pressurizing pump 45 functioning as a liquid flow unit can pressurize the reduced pressure liquid so that the liquid can flow from the degassing unit 21 toward the common liquid chamber 17.

The above embodiment may be modified as shown in the following modification.
Degassing of the liquid is not limited to pressure reduction through the hollow fiber membrane 22, and any method such as ultrasonic degassing or centrifugal degassing can be employed.

  In the pressure cleaning process, instead of releasing the capping in step S31, the air release valve 57 may be opened. According to this configuration, since the pressure cleaning can be performed while the capping is performed, scattering of the liquid flowing out from the nozzle 16 can be suppressed.

  -At least one of the filling of the common liquid chamber 17 with the liquid and the filling of the nozzle 16 with the liquid may be performed by performing steps S31 to S34 of the pressure cleaning process.

  The liquid ejected by the liquid ejecting unit may be liquid or liquid other than ink. For example, recording is performed by ejecting a liquid containing, in the form of dispersion, mixing, or dissolution, materials such as electrode materials and coloring materials (pixel materials) used in the manufacture of liquid crystal displays, EL (electroluminescence) displays, and surface emitting displays. May be configured to

  The medium is not limited to paper, but may be a plastic film, a plate, a panel or the like, or a cloth used for a textile printing apparatus or the like.

  11: liquid injection device, 12: liquid storage unit, 14: liquid flow passage, 16: nozzle, 17: common liquid chamber, 18: return flow passage, 19: open / close valve, 21: deaeration unit, 25: pressure reduction mechanism, 31: pressure adjustment unit, 32: flexible portion, 33: pressure chamber, 34: communication flow passage, 35: supply chamber, 36: urging member, 37: valve body, 41: bypass flow passage, 42: switching valve, 45: A pressurizing pump that functions as a liquid flow unit, 48: a filter that is an example of a foreign matter capture unit, 49: an air trap that is an example of a foreign matter capture unit.

Claims (9)

Multiple nozzles that can eject liquid,
A common liquid chamber for supplying liquid to the plurality of nozzles;
A liquid flow path for supplying a liquid stored in a liquid storage unit to the common liquid chamber;
A first liquid flow portion capable of pressurizing liquid in the liquid flow path;
A pressure adjustment unit provided between the first liquid flow unit and the common liquid chamber in the liquid flow path, the pressure adjustment unit adjusting the pressure of the liquid supplied to the common liquid chamber;
A return flow path connecting the common liquid chamber and the liquid storage unit;
A second liquid flow portion capable of depressurizing the liquid in the return flow path;
An on-off valve that closes the feedback flow path by being in a valve closing state;
Equipped with
Depending on the first fluid flowing section communicates the return flow path and the common liquid chamber by the on-off valve in the open state in a state in which pressurized liquid in the liquid flow path, the second liquid flow by reducing the pressure of the liquid in the common liquid chamber by part, a liquid-jet apparatus characterized and Turkey to flow toward the liquid in the common liquid chamber to the return flow path. A plurality of common liquid chambers are provided,
The liquid flow path has a plurality of branched liquid flow paths branched corresponding to each of the plurality of common liquid chambers on the common liquid chamber side with respect to the first liquid flowing portion,
The pressure adjusting unit is provided in each of the plurality of branched liquid flow paths corresponding to the plurality of common liquid chambers,
The liquid ejecting apparatus according to claim 1, wherein the return flow path has a plurality of branched return flow paths branched corresponding to each of the plurality of common liquid chambers. The liquid ejecting apparatus according to claim 2, further comprising a filter at a position between the first liquid flowing portion and the branched liquid flow path in the liquid flow path.   The liquid ejecting apparatus according to any one of claims 1 to 3, further comprising a degassing unit capable of degassing the liquid in the liquid flow path. The degassing unit has a decompression mechanism that decompresses the liquid in the liquid flow path for degassing,
5. The liquid ejecting apparatus according to claim 4, wherein the first liquid flowing unit supplies the liquid from the degassing unit toward the common liquid chamber in a pressurized state.   The pressure adjustment unit includes a supply chamber communicating with the liquid storage unit side of the liquid flow passage, a pressure chamber communicating with the common liquid chamber side of the liquid flow passage, and a flexible portion constituting the pressure chamber. A biasing member for biasing the volume of the pressure chamber in the increasing direction, and the pressure in the pressure chamber becomes lower than the pressure on the outside of the flexible portion, in accordance with the displacement of the flexible portion. The liquid injection device according to any one of claims 1 to 5, further comprising: a valve body that is displaced in a direction in which the pressure chamber communicates with the supply chamber. Multiple nozzles that can eject liquid,
A common liquid chamber for supplying liquid to the plurality of nozzles;
A liquid flow path for supplying a liquid stored in a liquid storage unit to the common liquid chamber;
A first liquid flow portion capable of pressurizing liquid in the liquid flow path;
A pressure adjustment unit provided between the first liquid flow unit and the common liquid chamber in the liquid flow path, the pressure adjustment unit adjusting the pressure of the liquid supplied to the common liquid chamber;
A return flow path connecting the common liquid chamber and the liquid storage unit;
A second liquid flow portion capable of depressurizing the liquid in the return flow path;
A maintenance method of a liquid injection device, comprising: an on-off valve that closes the return flow passage by being in a valve closing state,
With the liquid in the liquid flow path pressurized by the first liquid flow portion, the on-off valve is opened to communicate the common liquid chamber with the return flow path, and the second liquid flow portion And a liquid in the common liquid chamber is made to flow toward the return flow path by decompressing the liquid in the common liquid chamber. 8. The liquid ejecting apparatus according to claim 7, wherein when the liquid in the common liquid chamber is made to flow toward the return flow channel and is collected in the liquid storage unit, the liquid storage unit is opened to the atmosphere. Maintenance method. When not ejecting liquid from the nozzle, the maintenance method as set forth in claim 7 or 8, wherein the liquid in the common liquid chamber to cause flow toward the return flow path.