JP5509873B2 - Liquid ejecting apparatus and method of recovering nozzle in liquid ejecting apparatus - Google Patents

Description

  The present invention relates to a liquid ejecting apparatus such as an ink jet printer, and a nozzle recovery method in the liquid ejecting apparatus.

  2. Description of the Related Art Inkjet printers (hereinafter also referred to as “printers”) are widely known as liquid ejecting apparatuses that eject liquid onto a target. This printer performs printing (image formation) on a target by ejecting ink (liquid) supplied to the recording head from nozzles formed on the recording head.

  In such a printer, when the ink in the nozzles evaporates and decreases, the position of the meniscus rises from an appropriate position, and good ink ejection cannot be performed, resulting in a decrease in print quality. Therefore, in such a printer, as described in Patent Document 1, for example, the ink is pressurized and supplied from the ink cartridge side that contains the ink to the recording head side, the ink is filled in the nozzle, and the meniscus position is lowered. The nozzle recovery process is performed.

JP 2007-152725 A

  By the way, the rise of the meniscus position occurs for each nozzle. For this reason, when the nozzle recovery process is performed by supplying pressure to the ink as in the printer of Patent Document 1, the ink is also pressed against a normal nozzle having a meniscus at an appropriate position near the nozzle opening. Will be supplied. For this reason, the ink is pushed out of the nozzle opening and discharged from the normal nozzle, and there is a problem that a large amount of ink is wasted due to the recovery process of the nozzle.

  The present invention has been made in view of the above problems, and an object thereof is to provide a liquid ejecting apparatus capable of performing nozzle recovery processing while suppressing liquid consumption, and a liquid ejecting apparatus recovery method. There is.

  In order to achieve the above object, a liquid ejecting apparatus of the present invention includes a plurality of nozzles that eject liquid, and a liquid that supplies the liquid from an upstream side that is a liquid supply source side toward a downstream side that is the nozzle side. The liquid in the liquid supply flow channel can be sucked from the supply flow channel and a first position in the liquid supply flow channel, and the liquid can be discharged from the first position into the liquid supply flow channel A pump, a flow path valve provided in a second position upstream of the first position in the liquid supply flow path so that the liquid supply flow path can be opened and closed, the pump and the flow path valve Control means for controlling the drive of the nozzle to perform recovery processing of the nozzle, and the control means drives the pump to suck the liquid by sucking the pump in a state where the flow path valve is closed. Downstream from the second position in the supply channel After sucked Luo said liquid, said ejected liquid to the downstream side of the second position in the liquid supply passage to the pump by discharging driving the pump.

  According to this configuration, when the pump is driven to suck, the liquid on the downstream side of the second position in the liquid supply channel is sucked from the first position, so that the meniscus position of the liquid is upstream from the nozzle opening. Move in the direction toward. The liquid whose meniscus position has been moved to the upstream side due to suction driving of the pump receives the discharge pressure when the pump is subsequently driven to discharge and liquid is discharged from the first position into the liquid supply channel. Thus, the meniscus position moves to the downstream side, which is the nozzle opening side. Then, when the capillary force of the nozzle acts thereafter, the liquid meniscus position easily changes to an appropriate position near the nozzle opening, and the nozzle recovery process is completed. Thus, in the nozzle recovery process, the liquid meniscus position can be moved to an appropriate position without discharging the liquid outward from the nozzle opening. Accordingly, it is possible to perform the nozzle recovery process while suppressing the consumption of the liquid.

In the liquid ejecting apparatus according to the aspect of the invention, the liquid supply flow path may include a plurality of branch flows branched from the third position on the downstream side of the second position in the liquid supply flow path corresponding to the nozzles. The plurality of branch channels include a first channel constituting each branch channel and a second channel having a smaller channel cross-sectional area than the first channel, Of the first channel and the second channel, the first channel is connected to the nozzle.

  The position of the liquid meniscus is less likely to move as the cross-sectional area of the liquid supply flow path where the meniscus is formed is smaller. In this respect, according to this configuration, since the second flow channel having a smaller channel cross-sectional area than the first flow channel is provided in the liquid supply flow channel, the movement of the meniscus is changed to the first flow channel. It can be stopped near the boundary with the second flow path. Accordingly, it is possible to reduce the possibility that bubbles are mixed up to the upstream side of the branch point.

  In the liquid ejecting apparatus according to the aspect of the invention, the one-way valve that allows passage of the liquid from the upstream side to the downstream side in response to the pressure reduction on the downstream side is located upstream of the second position in the liquid supply channel. It was provided at the fourth position.

  According to this configuration, when the liquid on the downstream side of the flow path valve is supplied to the nozzle and the meniscus descends, the inside of the liquid supply flow path is depressurized by that amount. And with this pressure reduction, the liquid is supplied from the upstream side to the downstream side through the one-way valve. Then, since the liquid is supplied and the decompression in the liquid supply flow path is eliminated, the supply of the liquid via the one-way valve is interrupted. Therefore, it is possible to suppress excessive supply of liquid and discharge from the nozzle, and to easily adjust the pressure in the liquid supply flow path.

  The liquid ejecting apparatus of the present invention includes an ejecting unit that pressurizes the liquid in the liquid supply channel and ejects the liquid from the nozzle, and the control unit is configured to eject the liquid from the nozzle when the pump is driven. The ejecting means is driven in a second pressurizing mode in which the amount of liquid ejected from the nozzle is smaller than that in the first pressurizing mode in which the liquid is ejected and adhered to the target.

  According to this configuration, the liquid in the nozzle vibrates in accordance with the driving of the ejecting means, so that the meniscus position is easily moved. On the other hand, the nozzle whose meniscus position has risen to the upstream side of the ejection unit is not easily affected even when the ejection unit is driven. Therefore, in the nozzle whose meniscus position is raised, the meniscus position is less likely to move compared to a nozzle having a normal meniscus position. Therefore, the possibility that the meniscus position will rise too much can be reduced. Further, since the ejecting means is driven by the second pressurizing mode having a smaller ejection amount than that of the first pressurizing mode, the liquid discharge amount can be reduced.

  A method for recovering a nozzle in a liquid ejecting apparatus of the present invention includes: a plurality of nozzles that eject liquid; and a liquid supply channel that supplies the liquid from an upstream side that is a liquid supply source side to a downstream side that is the nozzle side. In a method for recovering a nozzle in a liquid ejecting apparatus, the liquid in the liquid supply flow channel can be sucked from the first position in the liquid supply flow channel and can be sucked into the liquid supply flow channel from the first position. The pump capable of discharging the liquid is sucked and driven in a state where a flow path valve provided at a second position upstream of the first position is closed, and the second in the liquid supply flow path A suction stage for sucking the liquid in the liquid supply channel from the downstream side of the position, and the pump is driven to discharge in a state in which the channel valve is closed, and the second in the liquid supply channel Downstream of the position And a discharge step of discharging the liquid sucked by the serial suction stage.

According to this configuration, the same function and effect as the invention relating to the liquid ejecting apparatus can be achieved.
In the method for recovering a nozzle in the liquid ejecting apparatus of the invention, the suction stage and the discharge stage are alternately performed a plurality of times.

  According to this configuration, even when there are nozzles that could not be recovered at one suction stage and at the discharge stage, the state of the nozzles can be recovered by repeating a plurality of times. That is, since the consumption of the liquid is suppressed even in the nozzle that has been recovered first, the recovery probability can be increased while suppressing the consumption of the liquid by performing the suction stage and the discharge stage a plurality of times.

In the method for recovering a nozzle in the liquid ejecting apparatus of the invention, the suction stage and the discharge stage are continuously performed.
When the pump maintains the suction state in which the liquid is sucked, pressure distribution is generated in the fluid supply flow path, and the meniscus may be lowered more easily as the nozzle is further away from the pump. In this respect, according to this configuration, since the pump is continuously driven after the pump is driven for suction, partial movement of the meniscus can be suppressed.

1 is a schematic diagram of a printer according to an embodiment. FIG. 2 is a schematic diagram of an ink supply system. FIG. 3 is a schematic cross-sectional view taken along arrow 3-3 in FIG. 2. Schematic diagram of the maintenance pump. (A), (b) is a cross-sectional schematic diagram of a recording head.

  Hereinafter, an embodiment in which a fluid ejecting apparatus of the invention is embodied in an ink jet printer will be described with reference to the drawings. In the following description, “left-right direction” and “up-down direction” refer to the left-right direction and the up-down direction indicated by arrows in FIG. 1, respectively. Further, when referring to the “front-rear direction”, the direction orthogonal to the paper surface of FIG.

  As shown in FIG. 1, an ink jet printer (hereinafter, also referred to as “printer”) 11 as a liquid ejecting apparatus prints the paper 12 and a transport unit 13 for transporting the paper 12 as a target. Recording head unit 15.

  The transport unit 13 includes a rectangular plate-shaped platen 17 that is long in the left-right direction. A drive roller 18 extending in the front-rear direction is disposed on the right side of the platen 17 so as to be rotationally driven by a drive motor 19, while a driven roller 20 extending in the front-rear direction is disposed on the left side of the platen 17 so as to be rotatable. Further, a tension roller 21 extending in the front-rear direction is rotatably disposed below the platen 17.

  An endless transport belt 22 having a large number of through holes is wound around the drive roller 18, the driven roller 20, and the tension roller 21 so as to surround the platen 17. In this case, the tension roller 21 is urged downward by a spring member (not shown), and by applying tension to the conveyor belt 22, looseness of the conveyor belt 22 is suppressed.

  Then, when the driving roller 18 is rotationally driven in the clockwise direction when viewed from the front side, the conveying belt 22 is rotated in the clockwise direction when the outer side of the driving roller 18, the tension roller 21, and the driven roller 20 is viewed from the front side. It has become. Further, when the sheet 12 is at a position facing the upper surface of the platen 17, the sheet 12 is sucked to the platen 17 side through the conveying belt 22 by a suction unit (not shown), and is conveyed from the upstream left side to the downstream right side. It has come to be.

  A pair of upper and lower paper feed rollers 23 for feeding a plurality of unprinted paper sheets 12 one by one onto the transport belt 22 one by one is provided on the upper left side of the driven roller 20. On the other hand, on the diagonally upper right side of the driving roller 18, a pair of upper and lower paper discharge rollers 24 for discharging the printed paper 12 one by one from the transport belt 22 are provided.

  As shown in FIGS. 1 and 2, the recording head unit 15 includes a plurality of (four in the present embodiment) recording heads 26 to 29 extending in the front-rear direction and spaced in the left-right direction. Is provided. In addition, on the nozzle formation surfaces 26a to 29a that are the lower surfaces of the recording heads 26 to 29, a large number of nozzles 30 are regularly formed at predetermined intervals in the front-rear direction so as to form nozzle rows along the front-rear direction. It is open. The nozzles 30 thus configured are supplied with the same type of ink (liquid) for each of the recording heads 26 to 29 and ejected from the nozzles 30.

  That is, as shown in FIG. 2, the first recording head 26 receives black ink from an ink cartridge 31 serving as a liquid supply source containing black ink via an ink flow path 32 serving as a liquid supply flow path. Is connected to the ink supply device 33. Similarly, the second to fourth recording heads 27 to 29 are connected to an ink supply device 33 that supplies ink from ink cartridges 31 containing inks of cyan, magenta, and yellow, respectively.

  However, since the configuration of the ink supply device 33 that supplies ink from each ink cartridge 31 to each recording head 26 to 29 is the same, FIG. 2 shows one ink supply device that supplies ink to the first recording head 26. Only 33 is shown together with the first recording head 26 and the ink cartridge 31. In the following description, the first recording head 26 and the ink supply device 33 that supplies ink to the first recording head 26 shown in FIG. 2 will be described as an example.

  As shown in FIGS. 2 and 3, a reservoir 36 communicating with the downstream side of the ink flow path 32 is formed in the first recording head 26 so as to extend in the front-rear direction along the nozzle row. A plurality of branch flow paths 35 individually corresponding to the nozzles 30 are branched from a plurality of positions in the extending direction of the reservoir 36. Note that the downstream end position in the reservoir 36 that is the branch point of the branch flow path 35 is a branch position PB as the third position.

  The branch channel 35 includes a cavity 37 as a first channel that communicates with the nozzle 30 and a communication channel 38 as a second channel that communicates the cavity 37 and the reservoir 36. Note that the cross-sectional area of the communication flow path 38 is smaller than the cross-sectional area of the cavity 37 in the direction orthogonal to the direction in which the ink flows (direction orthogonal to the paper surface in FIG. 3).

  Further, as shown in FIG. 3, a piezoelectric element 40 as an ejection unit is disposed at a position adjacent to the cavity 37 through a vibration plate 39 that forms one wall surface of the cavity 37. That is, the piezoelectric element 40 contracts and expands to vibrate the diaphragm 39, thereby changing the volume of the cavity 37 and ejecting ink from the nozzle 30. When the ink in the cavity 37 decreases with ejection, the ink is supplied from the ink cartridge 31 side via the communication channel 38, the reservoir 36, and the ink channel 32. Accordingly, the branch flow path 35, the reservoir 36, and the ink flow path 32 function as a liquid supply flow path that can supply ink from the upstream side that is the ink cartridge 31 side to the downstream side that is the nozzle 30 side.

  The nozzle 30 has a tapered portion 42 that gradually decreases in cross-sectional area from the upstream side to the downstream side that is connected to the cavity 37, and an opening 43 that communicates with the tapered portion 42 and opens to the nozzle forming surface 26a. It consists of and. When the nozzle 30 is filled with ink from the upstream side, a meniscus M is formed in the nozzle 30 and in the vicinity of the nozzle opening 44 opened in the nozzle forming surface 26a. The meniscus M is a curved surface that is formed by a capillary phenomenon so that the central portion of the ink rises so as to form a concave shape when viewed from the nozzle opening 44.

  In addition, as shown in FIG. 2, the ink cartridge 31 has a case 47 in which an ink pack 46 that contains ink and has flexibility. A pressure pump 49 is connected to the case 47 via an air flow path 48, and an upstream end of the ink flow path 32 is connected to the ink pack 46. Therefore, when the pressure pump 49 supplies air into the case 47 through the air flow path 48, the ink pack 46 is crushed and the ink in the ink pack 46 is supplied to the ink flow path 32. Yes.

  In the ink flow path 32, the pressure adjustment position PT as the fourth position allows the ink to pass from the upstream side to the downstream side as the downstream pressure is reduced, and the pressure in the ink flow path 32 is increased. A one-way valve 51 for adjustment is provided. In other words, the one-way valve 51 includes a storage chamber 52 that primarily stores ink pressurized and supplied from the ink cartridge 31, and a pressure chamber 53 that is positioned downstream of the storage chamber 52. The storage chamber 52 and the pressure chamber 53 are separated from each other by a partition wall portion 54, and communicated by a valve body 56 that is urged by a spring 55 in the valve closing direction and abuts against the partition wall portion 54 in the valve opening direction. It is supposed to be. A part of the pressure chamber 53 is constituted by a film 57 made of a flexible material (for example, synthetic resin or rubber). For example, a cantilever metal piece (for example, comb teeth) that can be displaced together with the film 57 is used. A piece of metal piece) is arranged at the contact point of the valve body 56.

  A flow path valve 60 capable of opening and closing the ink flow path 32 is provided at the open / close position PK as a second position downstream of the pressure adjustment position PT where the one-way valve 51 is provided. Furthermore, a maintenance pump 61 as a pump that can suck and discharge ink by changing the pressure in the ink flow path 32 is connected to the transformation position PH as the first position downstream of the open / close position PK. ing.

  As shown in FIG. 4, the maintenance pump 61 includes a flexible tube 62 and a pair of pressing rollers 63 and 64. The base end portion 62a of the tube 62 is connected to the ink flow path 32, while the distal end portion 62b of the tube 62 is open. The pair of pressing rollers 63 and 64 are arranged in a state where the tube 62 is clamped so as to be crushed from both sides. Further, the maintenance pump 61 includes a moving mechanism 65 (see FIG. 2) that reciprocally moves the pressing rollers 63 and 64 between a discharge position indicated by a solid line and a suction position indicated by a two-dot chain line in FIG. That is, the pressure rollers 63 and 64 positioned at the discharge position on the proximal end portion 62a side of the tube 62 move to the suction position side on the distal end portion 62b side from the discharge position, whereby the inside of the ink flow path 32 is reached. The ink is sucked into the tube 62. Further, the pressure rollers 63 and 64 positioned at the suction position move to the discharge position side, so that the ink in the tube 62 is pressed by the pressure rollers 63 and 64 and discharged to the ink flow path 32. It has become.

  Accordingly, the maintenance pump 61 is driven to perform suction and discharge by the movement mechanism 65 moving the pressing rollers 63 and 64. In the present embodiment, the volume in the tube 62 between the suction position and the retraction position is set so that the amount of ink sucked during suction driving is less than the total volume of the communication channels 38 connected to the reservoir 36. For example, it is about 0.03 cc.

  Further, as shown in FIG. 2, the printer 11 is provided with a control unit 67 as a control unit that performs overall control of the operating state of the printer 11. The control unit 67 drives and controls the piezoelectric element 40, the pressure pump 49, the flow path valve 60, and the moving mechanism 65 provided in each of the recording heads 26 to 29 so as to perform printing and the recovery process of the nozzles 30. It has become.

Next, the operation of the printer 11 configured as described above will be described below.
When printing is started in the printer 11, the control unit 67 creates an ink ejection timing for each nozzle 30 based on the print data, and in the first pressurization mode based on the ejection timing. The piezoelectric element 40 is driven. Then, the vibration plate 39 is displaced in the direction of decreasing the volume of the cavity 37 and ejects ink from the nozzle 30. In other words, the ink ejected from each nozzle 30 adheres to the paper 12 supported by the transport belt 22 and transported, whereby the paper 12 is printed.

  In addition, the flow path valve 60 is maintaining the valve open state at the time of printing. Therefore, when ink is ejected from the nozzle 30 and consumed, the reduced pressure accompanying the decrease in ink is transmitted to the one-way valve 51 via the reservoir 36 and the ink flow path 32, and the difference between the pressure chamber 53 and the atmosphere. Based on the pressure, the film 57 is bent and deformed toward the pressure chamber 53 side. Then, the valve body 56 moves to the valve opening position against the urging force of the spring 55, and the ink in the storage chamber 52 flows into the pressure chamber 53 side. When ink flows into the pressure chamber 53 and the chamber pressure increases, the urging force of the spring 55 overcomes and the valve body 56 moves to the valve closing position again.

  Accordingly, the one-way valve 51 allows the ink to pass from the upstream side to the downstream side in accordance with the pressure reduction on the downstream side, so that the consumed ink is supplied from the ink cartridge side. Therefore, even when ink is ejected from the nozzles during printing, the position of the meniscus M is located in the vicinity of the nozzle opening 44 as shown in FIG.

  However, if the period during which printing is not performed and ink is not ejected from the nozzles becomes long, the ink may evaporate from the nozzle openings 44 and the position of the meniscus M may rise (see FIG. 5A). In addition to ink evaporation, the position of the meniscus M may also rise in other situations, such as when the printer 11 receives an impact or when the end of the paper 12 contacts the nozzle opening 44.

  The ease of movement of the ink changes according to the flow path cross-sectional area of the flow path through which the ink flows, and the smaller the flow path cross-sectional area, the harder it is to move. In comparison, it is difficult for the inside of the communication channel 38 having a small channel cross-sectional area to move. Therefore, when the position of the meniscus M rises (that is, moves upstream), the position of the meniscus M easily stops in the communication channel 38. When the position of the meniscus M moves to the communication channel 38 upstream of the cavity 37 as described above, vibration cannot be transmitted to the ink even if the piezoelectric element 40 is driven. Good jetting cannot be achieved and print quality is degraded.

  Therefore, the control unit 67 executes the recovery process of the nozzle 30 when, for example, a recovery process execution command is received from the operation unit (not shown) from the user or when it is determined that a predetermined time has passed since the previous recovery process. . It is assumed that the pressure rollers 63 and 64 of the maintenance pump 61 are located at the discharge position and the flow path valve 60 is opened at the time of printing or standby during non-recovery processing.

  First, the controller 67 closes the flow path valve 60 and drives the moving mechanism 65 to move the pressing rollers 63 and 64 to the suction position side. Therefore, the maintenance pump 61 is driven to suck and gently sucks ink from the downstream side of the flow path valve 60 (suction stage).

  That is, for example, when accumulating negative pressure and eliminating the negative pressure to absorb ink vigorously, the ink is sucked upstream from some of the nozzles 30 and the branch flow path 35 to the meniscus M. The position may rise to the upstream side of the branch position PB. However, the gentler the suction, the more difficult it is to move the meniscus M at the nozzle 30 formed at the end of the recording head 26. Therefore, the suction speed is set to such an extent that the meniscus M in each nozzle 30 can be moved in the branch flow path according to the shape of the recording head 26 and the flow path resistance from each nozzle 30 to the maintenance pump 61. Then, for example, ink is sucked at 0.01 cc / second to 0.0001 cc / second.

  Further, when the maintenance pump 61 is driven to suck, the control unit 67 performs a second operation in which the amount of ink ejected from the nozzles 30 is smaller than that in the first pressurization mode in which ink is ejected onto the paper 12 and printing is performed. The piezoelectric element 40 is driven a plurality of times in a pressurizing manner. Then, since the vibration of the piezoelectric element 40 is transmitted to the ink in the cavity 37 via the vibration plate 39, the ink in the cavity 37 becomes easier to move. However, it is preferable that the second pressurization mode is a mode in which the piezoelectric element 40 is driven to the extent that ink is not ejected from the nozzle 30.

  Further, since the amount of ink sucked by the suction drive of the maintenance pump 61 is smaller than the total volume of the plurality of communication channels 38, the meniscus positioned in the communication channel 38 as shown in FIG. M receives an impact in the communication flow path 38 and vibrates, so that its position moves. On the other hand, as shown in FIG. 3, in the nozzle 30 in which the cavity 37 and the nozzle 30 are filled with ink and the meniscus M is located in the vicinity of the nozzle opening 44, the position of the meniscus M rises as shown in FIG. .

  If the ink is sucked into the tube 62, pressure distribution is generated in the ink flow path 32 and the reservoir 36, and the meniscus M may be lowered by some nozzles 30. Therefore, when the control unit 67 drives and controls the moving mechanism 65 to move the pressing rollers 63 and 64 to the suction position, the control unit 67 continuously moves the pressing rollers 63 and 64 to the discharge position. That is, the term “continuous” refers to the time before the partial movement of the meniscus M occurs after the maintenance pump 61 is driven to perform suction, and the maintenance pump 61 continuously performs suction drive and discharge drive. Whether or not the meniscus M is lowered can be determined, for example, by bringing an absorbing member into contact with the nozzle formation surfaces 26a to 29a and whether ink adheres to the absorbing member.

  The controller 67 opens the flow path valve 60 and controls the moving mechanism 65 so that the maintenance pump 61 is driven to discharge, and the tube 62 sucked from the ink flow path 32 in accordance with the previous suction drive. The ink inside is pushed out from the tube 62 and discharged to the ink flow path 32 (discharge stage). However, since the one-way valve 51 is provided on the upstream side of the ink flow path 32 from the transformation position PH to which the maintenance pump 61 is connected, the ejected ink is supplied to the downstream side. That is, the one-way valve 51 is configured so that the storage chamber 52 and the pressure chamber 53 communicate with each other when the pressure on the downstream side is reduced. Therefore, when the pressure on the downstream side is increased, the one-way valve 51 is on the upstream side. The transmission of the applied pressure is suppressed. Therefore, as shown in FIG. 5B, the meniscus M that has risen with the suction drive of the maintenance pump 61 moves down to the vicinity of the nozzle opening 44 as shown in FIG.

  On the other hand, as shown in FIG. 5 (a), the meniscus M located in the communication flow path 38 is in a state in which it is easily moved due to an impact with the suction drive of the maintenance pump 61. When 61 is driven to discharge, it moves into the cavity 37. Then, ink is supplied into the cavity 37 and the nozzle 30 by the capillary force, and the meniscus M is lowered to the nozzle opening 44 as shown in FIG.

  When the meniscus M that has been raised is lowered, ink is supplied from the ink cartridge 31 side. That is, on the downstream side of the one-way valve 51, the meniscus M that has risen in a state where the total amount of ink does not change is lowered, so that the inside of the ink flow path 32 is decompressed. Therefore, when the reduced pressure is transmitted to the pressure chamber 53 of the one-way valve 51, the film 57 is bent and deformed toward the pressure chamber 53, and the valve body 56 moves to the valve opening position against the urging force of the spring 55. As a result, ink flows from the storage chamber 52 on the ink cartridge 31 side into the pressure chamber 53. When the pressure reduction in the ink flow path 32 is eliminated, the urging force of the spring 55 moves the valve body 56 to the valve closing position, thereby interrupting the ink supply.

  Further, when the control unit 67 controls the moving mechanism 65 to move the pressing rollers 63 and 64 to the discharge position, the control unit 67 subsequently moves the pressing rollers 63 and 64 to the suction position side, and causes the maintenance pump 61 to perform suction driving and discharging. Execute driving several times alternately.

According to the above embodiment, the following effects can be obtained.
(1) When the maintenance pump 61 is driven to suck, ink downstream of the opening / closing position PK in the ink flow path 32 is sucked from the transformation position PH, so that the ink meniscus M is positioned upstream from the nozzle opening 44. Move in the direction toward. Then, when the maintenance pump 61 is driven to suck and the position of the meniscus M is moved to the upstream side, the maintenance pump 61 is driven to discharge and then ink is discharged from the transformation position PH into the ink flow path 32. In response to the discharge pressure, the position of the meniscus M moves to the downstream side, which is the nozzle opening 44 side. Then, when the capillary force of the nozzle 30 acts thereafter, the position of the ink meniscus M easily changes to an appropriate position near the nozzle opening 44, and the recovery processing of the nozzle 30 is completed. As described above, in the recovery process of the nozzle 30, the position of the ink meniscus M can be moved to an appropriate position without discharging the ink from the nozzle opening 44 to the outside. Accordingly, it is possible to perform the recovery process of the nozzles 30 while suppressing ink consumption.

  (2) The position of the ink meniscus M is more difficult to move as the channel cross-sectional area of the ink channel 32 where the meniscus M is formed is smaller. In that respect, since the communication channel 38 having a smaller channel cross-sectional area than the cavity 37 is provided in the ink channel, the movement of the meniscus M can be stopped near the boundary between the cavity 37 and the communication channel 38. it can. Accordingly, it is possible to reduce the possibility that bubbles are mixed up to the upstream side of the branch position PB.

  (3) When ink on the downstream side of the flow path valve 60 is supplied to the nozzle 30 and the meniscus M is lowered, the inside of the ink flow path 32 is depressurized by that amount. As the pressure is reduced, ink is supplied from the upstream side to the downstream side via the one-way valve 51. Then, since the ink is supplied and the decompression in the ink flow path 32 is eliminated, the supply of ink through the one-way valve 51 is interrupted. Therefore, it is possible to suppress the ink from being excessively supplied and discharged from the nozzle 30 and to easily adjust the pressure in the ink flow path 32.

  (4) Since the ink in the nozzle 30 vibrates in accordance with the driving of the piezoelectric element 40, the position of the meniscus M is easily moved. On the other hand, the nozzle 30 in which the position of the meniscus M rises to the upstream side of the piezoelectric element 40 is not easily affected even if the piezoelectric element 40 is driven. Therefore, in the nozzle 30 in which the position of the meniscus M is raised, the position of the meniscus M is less likely to move compared to the nozzle 30 in which the position of the meniscus M is normal. Therefore, the possibility that the position of the meniscus M will rise too much can be reduced. In addition, since the piezoelectric element 40 is driven by the second pressurization mode having a smaller ejection amount than the first pressurization mode, the ink discharge amount can be reduced.

  (5) Even when there is a nozzle 30 that could not be recovered at one suction stage and the discharge stage, the state of the nozzle 30 can be recovered by repeating a plurality of times. That is, since the consumption of ink is suppressed even in the nozzle 30 that has been recovered earlier, the recovery probability can be increased while suppressing the consumption of ink by performing the suction stage and the ejection stage a plurality of times.

  (6) When the maintenance pump 61 maintains the suction state where the ink is sucked, pressure distribution is generated in the ink flow path 32, and the meniscus M may be more likely to descend as the nozzle 30 is further away from the maintenance pump 61. In this respect, since the discharge pump is continuously driven after the maintenance pump 61 is driven for suction, partial movement of the meniscus M can be suppressed.

  (7) If the negative pressure of the maintenance pump 61 is accumulated and suctioned vigorously, the meniscus M may rise to the reservoir 36 and air bubbles may be mixed into the reservoir 36. In this respect, the suction force that drives the maintenance pump 61 is directly transmitted to the ink filled in the nozzle 30 or the branch flow path 35, thereby restricting the movement range of the meniscus M and suppressing air bubbles from entering the reservoir 36. can do.

In addition, you may change the said embodiment as follows.
In the above embodiment, when the maintenance pump 61 is driven to discharge and then suctioned, it may be driven at intervals without being driven continuously. That is, when the maintenance pump 61 is driven to discharge, since the pressure state in the ink flow path 32 is stable, the meniscus M can be allowed to move downstream due to capillary action.

  In the above embodiment, the recovery process of the nozzle 30 may be performed by one suction drive and discharge drive. That is, for example, when the number of the nozzles 30 where the meniscus M is rising is small, the recovery process of the nozzles 30 can be performed even if the number of suction driving and discharge driving is small. Further, each time the suction drive and the discharge drive are performed once, it is determined whether or not the nozzle 30 has recovered, and if there is a nozzle 30 that has not recovered, the recovery process of the nozzle 30 is executed again. May be.

  In the above-described embodiment, the piezoelectric element 40 may be driven even when the maintenance pump 61 is driven to discharge, or may be driven only during the discharge driving without being driven during the suction driving. The piezoelectric element 40 may not be driven when the maintenance pump 61 is driven.

In the above embodiment, the ejecting unit may be a heater element that ejects ink from the nozzle 30 by heating and vaporizing the ink.
In the above embodiment, the pressurization mode of the piezoelectric element 40 may be changed while the maintenance pump 61 is driven. For example, at the beginning of the suction drive, the meniscus M is located in the vicinity of the nozzle opening 44, so that the second pressurization mode is used. However, when the pressing rollers 63 and 64 approach the suction position, the meniscus M rises, so that the ejection of ink from the nozzles 30 is suppressed even when driven in the first pressure mode. Therefore, the pressurization mode may be changed so as to increase the amount of change of the cavity 37 with the movement of the pressing rollers 63 and 64. Further, when the maintenance pump 61 is driven to discharge, the pressurization mode may be changed so that the change amount of the cavity 37 is reduced as the pressing rollers 63 and 64 are moved. As the change in the cavity 37 is larger, the ink becomes easier to move. Therefore, it is possible to suppress the consumption of ink from the nozzle 30 and to make the ink easier to move.

  In the above embodiment, the one-way valve 51 may not be provided. In the case where the one-way valve 51 is not provided, it is preferable that the flow path valve 60 is closed when the maintenance pump 61 is driven to discharge. That is, the maintenance pump 61 is driven to discharge while the flow path valve 60 is closed, whereby the ink can be supplied to the nozzle 30 while suppressing the back flow of the ink to the ink cartridge 31 side. Further, regardless of the presence or absence of the one-way valve 51, the discharge driving may be performed with the flow path valve 60 closed.

  In the above embodiment, in the ink flow path 32, the one-way valve 51 may be provided at a position between the open / close position PK and the transformation position PH. That is, the maintenance pump 61 is driven by suction while the flow path valve 60 located upstream of the one-way valve 51 is closed, so that the upstream of the flow path valve 60 even if the one-way valve 51 is opened. Ink from the side is not supplied, and ink is sucked from the nozzle 30 side. On the other hand, when the maintenance pump 61 is driven to discharge, the one-way valve 51 is closed, so that ink is supplied to the nozzle 30 side. Therefore, since the ink sucked from the nozzle 30 side can be supplied to the nozzle 30 side, the recovery process can be performed while suppressing the discharge of the ink from the nozzle 30.

  In the above embodiment, the channel cross-sectional areas of the cavity 37 and the communication channel 38 may be the same. Moreover, you may comprise a branched flow path by connecting the several flow path from which a flow-path cross-sectional area differs. That is, by providing a plurality of channels having a small channel cross-sectional area, mixing of bubbles into the reservoir 36 can be suppressed.

  In the above embodiment, the maintenance pump 61 may be connected to the reservoir 36 so that ink in the reservoir 36 is sucked and discharged. That is, the branch position PB as the third position and the transformation position PH as the fourth position may be the same position.

  In the above embodiment, the maintenance pump 61 may be a piston pump or a diaphragm pump that changes the volume of the pump chamber by displacing the diaphragm. Further, a gear pump or a vane pump having an ink storage chamber is used. When suction driving is performed, ink is moved from the ink flow path 32 to the ink storage chamber. When discharging is driven, ink is transferred from the ink storage chamber to the ink flow path 32. You may make it make it.

  In the above embodiment, the amount of ink discharged by the maintenance pump 61 during discharge driving may be smaller than the amount of ink sucked during suction driving. That is, the meniscus that has started to move moves due to capillary action, and insufficient ink is supplied via the one-way valve 51. Therefore, by reducing the amount of ink forcibly supplied by the maintenance pump 61, it is possible to suppress ink leakage from the nozzles 30. Further, as a configuration for making the suction amount and the discharge amount different, one end of the maintenance pump 61 is connected to the upstream side of the one-way valve 51 in the ink flow path 32, and excess ink is upstream of the one-way valve 51. You may make it discharge to.

  In the above embodiment, the liquid ejecting apparatus is embodied in the ink jet printer 11, but a liquid ejecting apparatus that ejects or discharges liquid other than ink may be employed. The present invention can be used for various liquid ejecting apparatuses including a liquid ejecting head that ejects a minute amount of liquid droplets. In addition, a droplet means the state of the liquid discharged from the said liquid ejecting apparatus, and shall also include what pulls a tail in granular shape, tear shape, and thread shape. The liquid here may be any material that can be ejected by the liquid ejecting apparatus. For example, it may be in a state in which the substance is in a liquid phase, such as a liquid with high or low viscosity, sol, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals (metal melts ) And a liquid as one state of a substance, as well as a material in which particles of a functional material made of a solid such as a pigment or metal particles are dissolved, dispersed or mixed in a solvent. Further, representative examples of the liquid include ink and liquid crystal as described in the above embodiment. Here, the ink includes general water-based inks and oil-based inks, and various liquid compositions such as gel inks and hot melt inks. As a specific example of the liquid ejecting apparatus, for example, a liquid containing a material such as an electrode material or a color material used for manufacturing a liquid crystal display, an EL (electroluminescence) display, a surface emitting display, a color filter, or the like in a dispersed or dissolved state. It may be a liquid ejecting apparatus for ejecting, a liquid ejecting apparatus for ejecting a bio-organic material used for biochip manufacturing, a liquid ejecting apparatus for ejecting a liquid as a sample used as a precision pipette, a textile printing apparatus, a microdispenser, or the like. In addition, transparent resin liquids such as UV curable resin to form liquid injection devices that pinpoint lubricant oil onto precision machines such as watches and cameras, and micro hemispherical lenses (optical lenses) used in optical communication elements. A liquid ejecting apparatus that ejects a liquid onto the substrate or a liquid ejecting apparatus that ejects an etching solution such as an acid or an alkali to etch the substrate may be employed. The present invention can be applied to any one of these liquid ejecting apparatuses.

  DESCRIPTION OF SYMBOLS 11 ... Printer (liquid ejecting apparatus), 12 ... Paper (target), 30 ... Nozzle, 31 ... Ink cartridge (liquid supply source), 32 ... Ink channel (liquid supply channel), 35 ... Branch channel, 36 ... Reservoir (liquid supply flow path), 37 ... cavity (first flow path), 38 ... communication flow path (second flow path), 40 ... piezoelectric element (jetting means), 51 ... one-way valve, 60 ... flow Road valve, 61 ... Maintenance pump (pump), 67 ... Control unit (control means), PH ... transforming position (first position), PK ... opening / closing position (second position), PB ... branching position (third Position), PT ... pressure adjusting position (fourth position).

Claims (7)

A plurality of nozzles for ejecting liquid;
A liquid supply flow path for supplying the liquid from an upstream side which is a liquid supply source side toward a downstream side which is the nozzle side;
A pump capable of sucking the liquid in the liquid supply channel from a first position in the liquid supply channel and capable of discharging the liquid from the first position into the liquid supply channel;
A flow path valve provided in a second position on the upstream side of the first position in the liquid supply flow path so as to be able to open and close the liquid supply flow path;
Control means for controlling the drive of the pump and the flow path valve to perform recovery processing of the nozzle,
The control means causes the pump to suck the liquid from the downstream side of the second position in the liquid supply flow path by driving the pump with suction while the flow path valve is closed. The liquid ejecting apparatus according to claim 1, wherein the pump discharges the liquid to the downstream side of the second position in the liquid supply flow path by discharging the pump. The liquid supply flow path has a plurality of branch flow paths branched from the third position corresponding to the nozzles from a third position downstream of the second position in the liquid supply flow path,
The plurality of branch channels include a first channel constituting each branch channel and a second channel having a smaller channel cross-sectional area than the first channel,
2. The liquid ejecting apparatus according to claim 1, wherein, of the first flow path and the second flow path, the first flow path is connected to the nozzle. A one-way valve that allows passage of the liquid from the upstream side to the downstream side in accordance with the pressure reduction on the downstream side is provided at a fourth position that is upstream from the second position in the liquid supply channel. The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. Injecting means for injecting the liquid from the nozzle by pressurizing the liquid in the liquid supply channel,
The control means is configured to provide a second pressurizing mode in which the amount of liquid ejected from the nozzle is smaller than a first pressurizing mode in which the liquid is ejected from the nozzle and adhered to the target when the pump is driven. 4. The liquid ejecting apparatus according to claim 1, wherein the ejecting unit is driven. In a method for recovering a nozzle in a liquid ejecting apparatus, comprising: a plurality of nozzles that eject liquid; and a liquid supply passage that supplies the liquid from an upstream side that is a liquid supply source side to a downstream side that is the nozzle side.
A pump capable of sucking the liquid in the liquid supply channel from a first position in the liquid supply channel and discharging the liquid into the liquid supply channel from the first position; The liquid supply flow is driven from the downstream side of the second position in the liquid supply flow path by sucking and driving the flow path valve provided at the second position upstream from the first position. A suction stage for sucking the liquid in the channel;
A discharge stage in which the pump is driven to discharge while the flow path valve is closed, and the liquid sucked in the suction stage is discharged to the downstream side of the second position in the liquid supply flow path. A method for recovering a nozzle in a liquid ejecting apparatus. 6. The method for recovering a nozzle in a liquid ejecting apparatus according to claim 5, wherein the suctioning step and the discharging step are alternately performed a plurality of times. The method for recovering a nozzle in a liquid ejecting apparatus according to claim 5, wherein the suctioning step and the discharging step are continuously performed.

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