JP5120147B2 - Maintenance method of liquid discharge head and liquid discharge apparatus - Google Patents

Description

  The present invention relates to a liquid ejection head maintenance method in a liquid ejection apparatus including a plurality of liquid ejection heads that eject different types of liquids, and a liquid ejection apparatus.

As an example of the liquid ejecting apparatus, there is an ink jet printer including a plurality of ink jet heads that eject inks of different colors. In such an ink jet printer, at the time of maintenance of the ink jet head, the wiper is moved along the longitudinal direction of the ink jet head while being brought into contact with the nozzle surface on which a plurality of nozzles are arranged. Wiping for wiping off foreign matters such as paper dust is performed (see, for example, Patent Document 1).
JP 2006-212863 A

  However, when performing maintenance as described above, if ink of a different color from the ink ejected by the target head that is the target of wiping operation by the wiper adheres to the wiper, for example, between a plurality of target heads When one wiper is shared, color mixing occurs on the nozzle surface of the target head.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid discharge head maintenance method and a liquid discharge apparatus that can prevent liquid mixture.

The maintenance method for a liquid discharge head according to the present invention has a nozzle surface on which a plurality of nozzles are respectively arranged, and a plurality of liquid discharge heads that discharge different types of liquids and a foreign matter attached to the nozzle surface. A maintenance method for a liquid ejection head in a liquid ejection apparatus including a wiper for wiping, wherein the maintenance method is separated from the nozzle surface of a target head to be subjected to a wiping operation by the wiper among a plurality of liquid ejection heads A liquid attaching step for attaching a liquid discharged from the target head to the facing wiper, and after the liquid attaching step, a part of the wiper is positioned on the target head side with respect to the nozzle surface. And the target so that the wiper is in one of a state where the wiper is in contact with the nozzle surface. The head and the wiper are relatively moved, and the target head and the wiper are relatively moved along the longitudinal direction of the target head while the wiper and the nozzle surface of the target head are opposed to each other. A wiping step for wiping off foreign matter adhering to the nozzle surface. In the liquid adhesion step, the target head and the wiper are relatively moved along the longitudinal direction of the target head while the wiper and the nozzle surface of the target head are spaced apart from each other, and in the wiping step, An actuator that causes the wiper to be disposed at an initial position at which the wiping operation on the target head is started and generates ejection energy for ejecting liquid from the nozzle until the wiper is disposed at the initial position. A flushing operation is performed by driving, the liquid is ejected from all the nozzles of the target head by the flushing operation, and the ejected liquid is adhered to the wiper. The liquid adhering step and the wiping step are repeated as many times as the number of the liquid ejecting heads, with a plurality of liquid ejecting heads as the target heads in order.
According to these configurations, the liquid discharged from the target head can be attached to the wiper before the wiper is brought into contact with the nozzle surface to wipe the nozzle surface of the target head. Therefore, even when a different type of liquid from the liquid ejected by the target head is attached to the wiper, the liquid can be washed away or diluted. Therefore, when performing wiping, it is possible to prevent a liquid of a different type from the liquid ejected by the target head from adhering to the nozzle surface of the target head to be mixed. Further, the nozzle surfaces of all the liquid discharge heads can be wiped. Further, a special mechanism for attaching the liquid to the wiper is not required, and the liquid can be easily attached to the wiper.

In addition, the liquid ejection device of the present invention has a nozzle surface on which a plurality of nozzles are disposed, and wipes off foreign matter adhering to the plurality of liquid ejection heads that eject different types of liquid from each other. A wiper, a first moving mechanism that relatively moves the liquid discharge head and the wiper in a direction orthogonal to the nozzle surface, and the liquid discharge head and the wiper are moved to the liquid while the wiper and the nozzle surface are opposed to each other. A part of the wiper with respect to the nozzle surface from a second moving mechanism that moves relative to the longitudinal direction of the discharge head and a state in which the wiper is separated from the nozzle surface on a side opposite to the liquid discharge head. And the state where the wiper is in contact with the nozzle surface. As includes a first moving control means for controlling driving of the first moving mechanism, and a second movement control means for driving the second moving mechanism. The liquid ejection head includes an actuator that generates ejection energy for ejecting liquid from the nozzle, and is controlled by the second movement control unit before the control by the first movement control unit is performed. By controlling, the nozzle surface of the target head that is a target to be wiped by the wiper among the plurality of liquid ejection heads and the wiper are moved along the longitudinal direction of the target head while being spaced apart, A flushing operation in which the wiper is disposed at an initial position where the wiping operation on the target head is started, and the actuator is driven to discharge liquid from all the nozzles until the wiper is disposed at the initial position. The liquid ejected from the target head is attached to the wiper. A plurality of the liquid discharge heads are arranged along a width direction orthogonal to the longitudinal direction, a third moving mechanism for moving the wiper along the width direction, and a plurality of the liquid discharge heads in order. Third movement control means for driving the third movement mechanism after the nozzle surface is wiped off by the wiper so as to be a target head is further provided.

According to these configurations, the liquid discharged from the target head can be attached to the wiper before the wiper is brought into contact with the nozzle surface to wipe the nozzle surface of the target head. Therefore, even when a different type of liquid from the liquid ejected by the target head is attached to the wiper, the liquid can be washed away or diluted. Therefore, when performing wiping, it is possible to prevent a liquid of a different type from the liquid ejected by the target head from adhering to the nozzle surface of the target head to be mixed. Further, if the wiper has a length corresponding to the width of one liquid discharge head, the nozzle surfaces of all the liquid discharge heads can be wiped while being moved by the third moving mechanism. Therefore, the apparatus can be reduced in size. Further, a special mechanism for attaching the liquid to the wiper is not required, and the liquid can be easily attached to the wiper. In addition, the conversion from the operation of attaching the liquid to the wiper to the wiping operation of the nozzle surface can be performed smoothly.

  In the liquid ejection head maintenance method of the present invention, the liquid adhering to the wiper may be absorbed by the liquid absorbent material after the wiping step. According to this configuration, it is possible to prevent a mixed liquid from occurring when the next wiping is performed.

  In the liquid ejection head maintenance method of the present invention, in the liquid adhesion step, the liquid ejection head and the wiper may be relatively moved in a direction opposite to a movement direction during the wiping step. According to this configuration, since the liquid adhesion step and the wiping step can be performed during the operation of reciprocating the wiper once, there is no waste in the movement of the wiper.

  In the liquid ejection head maintenance method of the present invention, in the liquid adhesion step, the actuator may be driven to eject the liquid only from the nozzle located in a region facing the wiper on the nozzle surface. According to this configuration, since it is not necessary to discharge the liquid from all the nozzles in order to make the liquid adhere to the wiper, the consumption of the liquid can be suppressed.

  In the liquid ejection apparatus according to the aspect of the invention, it is preferable that the first movement mechanism moves the liquid ejection head. According to this configuration, since a mechanism for moving the wiper in a direction orthogonal to the nozzle surface is unnecessary, the device configuration can be simplified.

  In the liquid ejection apparatus of the present invention, the flushing operation may be performed by driving only the actuator corresponding to the region of the nozzle surface facing the moving wiper. According to this configuration, since the liquid adheres to the wiper in a state where the liquid is discharged only from the region where the wiper faces, the consumption of the liquid can be suppressed.

As described above, the liquid discharge head maintenance method and the liquid discharge apparatus may attach the liquid discharged from the target head to the wiper before wiping the nozzle surface of the target head by bringing the wiper into contact with the nozzle surface. it can. Therefore, even when a different type of liquid from the liquid ejected by the target head is attached to the wiper, the liquid can be washed away or diluted. Therefore, when performing wiping, it is possible to prevent a liquid of a different type from the liquid ejected by the target head from adhering to the nozzle surface of the target head to be mixed.
Furthermore, the maintenance method of the liquid discharge head can wipe the nozzle surfaces of all the liquid discharge heads. Further, a special mechanism for attaching the liquid to the wiper is not required, and the liquid can be easily attached to the wiper.
Furthermore, in the liquid ejection device, if the wiper has a length corresponding to the width of one liquid ejection head, the nozzle surfaces of all the liquid ejection heads are wiped while being moved by the third movement mechanism. be able to. Therefore, the apparatus can be reduced in size. Further, a special mechanism for attaching the liquid to the wiper is not required, and the liquid can be easily attached to the wiper. In addition, the conversion from the operation of attaching the liquid to the wiper to the wiping operation of the nozzle surface can be performed smoothly.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a schematic side view showing the overall configuration of the ink jet printer according to the first embodiment of the present invention. FIG. 2 is a schematic plan view of a main part of the ink jet printer shown in FIG.

  As shown in FIG. 1, the ink jet printer (hereinafter simply referred to as “printer”) 1 of the present embodiment is a color ink jet printer including four ink jet heads 2. A paper feed tray 11 and a paper discharge tray 12 are respectively provided on the left and right sides of the printer 1 in FIG. Furthermore, a transport mechanism 13 that transports the paper P in the paper transport direction (the direction from the left to the right in FIG. 1) while facing the nozzle surface 2a that is the lower surface of the inkjet head 2 is provided. As shown in FIG. 2, the printer 1 is provided with a maintenance unit 30 for performing maintenance on the inkjet head 2. Further, as shown in FIG. 1, the printer 1 includes a control device 70 that controls the operation of the printer 1.

  In the vicinity of the paper feed tray 11, there is provided a pair of feed rollers 5 that sandwich the paper P placed on the paper feed tray 11 and feed it to the right in FIG. The paper P sent out by the feed roller pair 5 is supplied to the transport mechanism 13.

  The transport mechanism 13 includes two belt rollers 6 and 7 and an endless transport belt 8 spanned between the belt rollers 6 and 7. As shown in FIG. 1, among the belt rollers 6 and 7, the belt roller 6 located on the downstream side in the conveying direction, that is, on the right side in the drawing, is rotationally driven clockwise in the drawing by the drive motor 6a. In a region surrounded by the conveyor belt 8, a substantially rectangular parallelepiped platen 15 that supports the conveyor belt 8 from the inner peripheral surface side is disposed. Further, a nip roller 4 that presses the paper P sent out from the paper feed tray 11 by the feed roller pair 5 against the transport surface 8 a that is the outer peripheral surface of the transport belt 8 is disposed at a position facing the belt roller 7.

  Further, a peeling member 14 is provided between the conveyance belt 8 and the paper discharge tray 12. The peeling member 14 is configured to peel the paper P held on the conveyance surface 8 a of the conveyance belt 8 from the conveyance surface 8 a and guide it toward the paper discharge tray 12.

  As shown in FIG. 1, the lower surface of the inkjet head 2 is a nozzle surface 2 a on which a large number of nozzles 10 (see FIGS. 4 and 5) are formed, and is opposed to the conveyance surface 8 a of the conveyance belt 8. The four inkjet heads 2 correspond to four colors of ink (magenta, yellow, cyan, and black), respectively, and eject inks of different colors. Each inkjet head 2 has a rectangular parallelepiped shape that is long in a direction (main scanning direction) orthogonal to the paper transport direction in plan view. The four inkjet heads 2 are fixed to a substantially square frame 3 in plan view so that they are aligned along the paper transport direction. That is, the printer 1 is a line type printer.

  The frame 3 is supported by a frame moving mechanism 51 so as to be movable up and down. As shown in FIG. 2, the frame moving mechanism 51 is disposed on both sides of the frame 3 along the paper conveyance direction (vertical direction in the figure). Each frame moving mechanism 51 includes a drive motor 52 that is a drive source for vertical movement, a pinion gear 53 that is fixed to the shaft of each drive motor 52, a rack gear 54 that meshes with each pinion gear 53, and a pinion gear 53. And a guide 55 arranged at a position sandwiching the rack gear 54. Among these, the drive motor 52 and the guide 55 are fixed to the main body frame 1 a of the printer 1, and the rack gear 54 is erected on the frame 3.

  In this configuration, when the two drive motors 52 are synchronized and each pinion gear 53 is rotated in the forward and reverse directions, the rack gear 54 is moved in the vertical direction. As the rack gear 54 moves up and down, the frame 3 and the four inkjet heads 2 move up and down.

  Normally, the frame 3 is arranged at a printing position (position shown in FIG. 1) where the four inkjet heads 2 eject ink onto the paper P and print. At this time, a slight gap is formed between the nozzle surface 2a of the ink jet head 2 and the transport surface 8a of the transport belt 8 to be a part of the paper transport path. Then, when the paper P transported by the transport belt 8 sequentially passes immediately below the nozzle surface 2a, ink droplets of each color are ejected from the nozzle 10 toward the upper surface of the paper P, whereby the paper P A desired color image is formed on the top. The frame 3 is moved by the frame moving mechanism 51 during maintenance of the inkjet head 2 to be described later, and is disposed above the printing position.

  As shown in FIG. 2, the frame 3 is attached with an ink absorber 19 extending in the paper transport direction. More specifically, the ink absorber 19 is attached to the side surface of the portion of the frame 3 that extends in the paper transport direction on the left side in FIG. The ink absorber 19 is for absorbing ink adhering to the wiper 45 described later, and moves up and down together with the inkjet head 2 by driving the frame moving mechanism 51.

  Next, the configuration of the inkjet head 2 will be described in more detail with reference to FIGS. FIG. 3 is a plan view of the inkjet head 2. FIG. 4 is an enlarged view of a region surrounded by a one-dot chain line in FIG. In FIG. 4, for convenience of explanation, what is to be drawn with a broken line below an actuator unit 21 to be described later (aperture 92, pressure chamber 91 and nozzle 10 to be described later) is drawn with a solid line. FIG. 5 is a partial cross-sectional view of the inkjet head 2.

  As shown in FIG. 3, the inkjet head 2 has a flow path unit 9 having a substantially rectangular shape elongated in the main scanning direction in plan view, and four trapezoidal shapes fixed to the upper surface of the flow path unit 9 in a staggered manner. Actuator unit 21 is included. More specifically, the four actuator units 21 are arranged such that the upper side (trapezoid upper base) and the lower side (trapezoid lower bottom) of the upper surface of the flow path unit 9 coincide with the longitudinal direction of the flow path unit 9, and The oblique sides of the adjacent actuator units 21 are parallel to each other and are arranged so that the positions of the flow path units 9 in the longitudinal direction are the same.

  The inkjet head 2 has a reservoir unit (not shown) that supplies ink to the flow path unit 9 to which the actuator unit 21 is fixed as described above, and a driver IC 16 that generates a drive signal that drives the actuator unit 21 (see FIG. 7) is assembled.

  As shown in FIG. 4, a large number of nozzles 10 arranged in a matrix form openings in regions facing the actuator units 21 on the lower surface of the flow path unit 9. On the upper surface of the flow path unit 9, there are opened pressure chambers 91 that communicate with the nozzles 10 and are arranged in a matrix. The pressure chamber 91 has a substantially rhombus shape with rounded corners in plan view. One actuator unit 21 is arranged so as to cover many pressure chambers 91. Here, the actuator unit 21 includes a plurality of actuators corresponding to the pressure chambers 91 and has a function of selectively giving ejection energy to the ink in the pressure chambers 91.

  Further, as shown in FIG. 3, a total of ten ink supply ports 80 are opened on the upper surface of the flow path unit 9 corresponding to the ink outflow flow paths (not shown) of the reservoir unit. Each of the ink supply ports 80 is formed so as to avoid the adhesion region of the actuator unit 21.

  As shown in FIG. 3, the flow path unit 9 includes a manifold flow path 81 communicating with the ink supply port 80, and a region branched from the manifold flow path 81 and facing the actuator unit 21. A plurality of sub-manifold channels 81a extending in the longitudinal direction are formed. Further, as shown in FIG. 5, an individual ink flow path 95 extending from the sub-manifold flow path 81a to the nozzle 10 via the pressure chamber 91 and the aperture 92 and the pressure chamber 91 is formed inside the flow path unit 9. . That is, the same number of individual ink flow paths 95 as the nozzles 10 are formed so as to correspond to the respective nozzles 10 (pressure chambers 91).

  Thereby, the ink from the reservoir unit is supplied to the manifold channel 81 via the ink supply port 80 and further distributed to the pressure chambers 91. When the ejection energy is selectively given to the pressure chamber 91 by the actuator unit 21, the pressure of the ink in the pressure chamber 91 rises, and the ink is ejected from the nozzle 10 communicating with the pressure chamber 91.

  As shown in FIG. 5, the flow path unit 9 includes nine plates 82 to 90 made of a metal material such as stainless steel. By laminating these plates 82 to 90 while being aligned with each other, the through holes formed in the plates 82 to 90 are connected to each other, and the manifold channel 81, the sub manifold channel 81a, and the sub manifold channel 81a are connected in the channel unit 9. A large number of individual ink flow paths 95 extending from the outlet of the manifold flow path 81 a to the nozzle 10 through the aperture 92 and the pressure chamber 91 are formed.

  Further, as shown in FIG. 1, the inkjet head 2 includes four ink cartridges 18 arranged in parallel in the paper conveyance direction below the conveyance mechanism 13 and a tube (not shown) via a pump 17 (see FIG. 7). ). The four ink cartridges 18 respectively correspond to four color inks (magenta, yellow, cyan, and black), and the pump 17 is disposed in the ink jet head 2 that discharges the corresponding color of the ink in the ink cartridge 18. It is for sending forcibly. Accordingly, by driving the pump 17, the ink in the manifold channel 81, the sub-manifold channel 81 a, and the individual ink channel 95 is pressurized, and air, dust, deteriorated ink, etc. mixed in the inkjet head 2. The purge operation for forcibly discharging the foreign matter together with the ink can be performed. The pump 17 is stopped during image formation on the paper P. The stopped pump 17 has an ink flow path formed therein so that the ink cartridge 18 and the inkjet head 2 communicate with each other.

  Next, the maintenance unit 30 will be described with further reference to FIG. FIG. 6 is a schematic side view of the maintenance unit 30. As shown in FIGS. 2 and 6, the maintenance unit 30 includes an X stage 31 that can move in the main scanning direction (X direction), and a wiping unit that can move in the paper transport direction (Y direction) on the top surface of the X stage 31. 40 and a moving tray 61 fixed to the left side surface of the X stage 31 in FIGS.

  The X stage 31 extends along the paper transport direction and is slidably supported by a pair of guide rails 32 extending in the main scanning direction in the vicinity of both ends in the paper transport direction. The extension / extension of the X stage 31 in the paper conveyance direction is equal to or longer than the length of the four inkjet heads 2 arranged in the paper conveyance direction. In addition, the X stage 31 is threadedly engaged with a ball screw 33 extending in the main scanning direction in parallel with the guide rail 32 at the lower part thereof. The drive motor 34 connected to the end of the ball screw 33 rotates the ball screw 33 so that the X stage 31 can move in the main scanning direction.

  The moving tray 61 fixed to the X stage 31 is a rectangular plate member in plan view, and supports the waste ink tray 62. Accordingly, the waste ink tray 62 can move in the main scanning direction as the X stage 31 moves. As will be described later, the waste ink tray 62 has a bottom surface that can be opposed to the four inkjet heads 2 when arranged at the ink receiving position (see FIG. 9C).

  The wiping unit 40 includes a Y stage 41, a wiper 45, a holder 46, and a discharge tray 47. The Y stage 41 is slidably supported by a pair of guide rails 42 laid on the upper surface of the X stage 31 so as to extend in the paper transport direction. Further, the Y stage 41 is screwed into a ball screw 43 extending in parallel to the guide rail 42, that is, in the paper transport direction. The drive motor 44 connected to the end of the ball screw 43 rotates the ball screw 43, so that the Y stage 41 can move in the paper transport direction. As shown in FIG. 6, the upper surface of the Y stage 41 is located above the waste ink tray 62.

  The wiper 45 is a rectangular plate member made of an elastic material such as rubber or resin for wiping off foreign matters such as ink and paper dust attached to the nozzle surface 2a. The holder 46 is fixed to the upper surface of the Y stage 41, and supports the wiper 45 so that the wiper 45 is inclined at a predetermined angle with respect to the nozzle surface 2a. The discharge tray 47 is fixed to the upper surface of the Y stage 41 together with the holder 46, and has an inclined surface that is inclined from the vicinity of the lower end of the wiper 45 toward the waste ink tray 62. As shown in FIG. 2, the wiping portion of the wiper 45 (the portion to be wiped in contact with the nozzle surface 2 a) is formed slightly longer than the width of the inkjet head 2 (length along the paper transport direction). The ink wiped off by the wiper 45 moves to the waste ink tray 62 via the discharge tray 47.

  In this way, the holder 46 that supports the wiper 45 is fixed to the Y stage 41 that can move in the paper transport direction, and the Y stage 41 is supported by the X stage 31 that can move in the main scanning direction. Therefore, the wiper 45 is movable in the paper transport direction and the main scanning direction.

  Here, the control device 70 will be described. The control device 70 is constituted by, for example, a general-purpose personal computer. Such a computer stores hardware such as a CPU, ROM, RAM, and hard disk, and various software including a program for controlling the overall operation of the printer 1 is stored in the hard disk. Then, by combining these hardware and software, later-described units 71 to 78 (see FIG. 7) are constructed.

  As shown in FIG. 7, which is a block diagram showing a schematic configuration of the control device 70, the control device 70 includes a paper transport control unit 71, a head control unit 72 including an ink discharge control unit 73 and a purge control unit 74, and a frame. A position control unit 75 and a wiper control unit 76 including an X direction movement control unit 77 and a Y direction movement control unit 78 are provided.

  The paper transport control unit 71 controls the transport of the paper P by the transport mechanism 13 by controlling the drive motor 6 a that drives the belt roller 6 of the transport mechanism 13.

  The ink ejection control unit 73 of the head control unit 72 individually controls the ejection of ink from the plurality of nozzles 10 of the inkjet head 2 by controlling the driver IC 16 that generates a drive signal to the actuator unit 21. The ink ejection control unit 73 ejects ink droplets from the nozzles 10 based on image data supplied from the outside, whereby an image is formed on the paper P. In addition, the ink ejection control unit 73 ejects ink droplets from the nozzles 10 separately from the image formation on the paper P, whereby a flushing operation described later is performed.

  The purge control unit 74 of the head control unit 72 controls the driving of the pump 17 so as to execute the purge operation. When the pump 17 is driven, pressure is applied to the ink in the inkjet head 2 and the ink is forcibly discharged from all the nozzles 10.

  The frame position control unit 75 controls the height position of the inkjet head 2 and the ink absorber 19 fixed to the frame 3 by controlling the drive motor 52 of the frame moving mechanism 51. In the present embodiment, the frame 3 is arranged at four different height positions, which are a retracted position, a wipe position, a purge position, and a printing position, under the control of the frame position control unit 75.

  The wiper control unit 76 is a part that performs relative movement of the wiping unit 40 facing the inkjet head 2, and the X-direction movement control unit 77 is a drive that drives the ball screw 33 that extends in the main scanning direction of the maintenance unit 30. The movement of the X stage 31 is controlled by controlling the motor 34. Thereby, the positions of the waste ink tray 62 and the wiping unit 40 in the main scanning direction can be controlled. The Y-direction movement control unit 78 controls the movement of the Y stage by controlling the drive motor 44 that drives the ball screw 43 extending in the paper conveyance direction of the maintenance unit 30. Thereby, the position of the wiping unit 40 in the paper conveyance direction can be controlled.

  Next, a maintenance method performed in the printer 1 will be described with reference to FIGS. FIG. 8 is a flowchart showing the operation of the printer 1 during maintenance. 9 and 10 are diagrams for explaining the movement of the inkjet head 2 and the maintenance unit 30 during maintenance.

  Here, the maintenance of the inkjet head 2 includes a purge operation for discharging the ink in the nozzles 10 and a wipe operation for wiping off ink adhering to the nozzle surface 2a by the purge operation. By performing the purge operation, foreign matter in the inkjet head 2 is discharged. Further, by performing the wiping operation, foreign matters are removed from the nozzle surface 2a to obtain a clean surface, and the ejection characteristics are restored. Maintenance of the ink jet head 2 is started when the ink jet printer 1 is turned on, after a predetermined time has elapsed since the power was turned on, before printing is started, or when an instruction is given from the user.

  It should be noted that before the maintenance is started, that is, when the maintenance is not performed, the maintenance unit 30 has the waste ink tray 62 and the wiping unit 40 disposed at a standby position where they do not face the nozzle surfaces 2a of the four inkjet heads 2. Yes. The standby position is a position adjacent to the left side with respect to the main scanning direction, as shown in FIG. At this time, as shown in FIG. 2, the wiping unit 40 is located in the vicinity of the inkjet head 2 located on the most upstream side in the paper conveyance direction.

  When performing maintenance in the printer 1, first, as shown in FIG. 9A, the inkjet head 2 positioned at the printing position (position indicated by the broken line in the drawing) is moved upward by the control of the frame position control unit 75. Move (S11). More specifically, at this time, the inkjet head 2 moves to a retreat position where the height position of the nozzle surface 2 a is higher than the height position of the tip of the wiper 45.

  Subsequently, as shown in FIG. 9B, the X stage 31 is moved rightward in FIG. 9 by the control of the X direction movement control unit 77, and at the same time, the nozzle 10 is controlled by the control of the ink discharge control unit 73. Then, a flushing operation for ejecting ink is performed, and ink is adhered to the wiper 45 (S12: liquid adhesion step). That is, at this time, the waste ink tray 62 and the wiping unit 40 move from the standby position toward an initial position where the waste ink tray 62 faces the nozzle surfaces 2a of the four inkjet heads 2. And the ink discharged from the target head which is the inkjet head 2 which opposes at this time among the four inkjet heads 2 adheres to the wiper 45.

  In S <b> 12, the ink ejection control unit 73 performs control so that ink is ejected only from the nozzles 10 disposed in the region facing the wiper 45 on the nozzle surface 2 a. That is, the ink ejection control unit 73 controls the driver IC 16 of the target head that faces the wiper 45 that moves from the standby position to the initial position. Then, control is performed so that the flushing area from which ink is ejected moves along with the movement of the wiper 45 on the nozzle surface 2 a of the target head. At this time, since the inkjet head 2 is disposed at the retracted position, the tip of the wiper 45 does not contact the nozzle surface 2a of the target head. At this time, if the amount of ink adhering to the wiper 45 is large, excess ink moves from the wiper 45 to the waste ink tray 62 via the discharge tray 47. Even if another color of ink adheres to the wiper 45, it is diluted or replaced by the ink discharged by the flushing operation, so that it is possible to prevent ink color mixing in the wiping step described later.

  Thereafter, as shown in FIG. 9C, the inkjet head 2 is moved to a purge position below the retracted position by the control of the frame position control unit 75, and the pump 17 is driven by the control of the purge control unit 74. The purge operation is executed (S13: purge step). At this time, the ink discharged from the nozzle 10 falls to the waste ink tray 62, and the ink dropped to the waste ink tray 62 is sucked by a pump (not shown) and stored in the waste ink tank.

  Next, under the control of the frame position control unit 75, the inkjet head 2 is moved to a wipe position where the height position of the nozzle surface 2 a is slightly lower than the height position of the tip of the wiper 45. Further, under the control of the X-direction movement control unit 77, the X stage 31 is moved toward the left in the drawing as shown in FIG. At this time, the wiper 45 moves from the initial position to the standby position while being in contact with the nozzle surface 2a of the target head, and wipes off foreign matter adhering to the nozzle surface 2a (S14: wiping step).

  Further, as shown in FIG. 10 (e), the ink absorber 19 attached to the frame 3 lowers the frame 3 to a position where it contacts the wiper 45 and adheres to the wiper 45 by the control of the frame position control unit 75. The ink thus absorbed is absorbed by the ink absorber 19 (S15).

  Subsequently, it is determined whether or not wiping of all inkjet heads 2 has been completed (S16). If it is determined that wiping of all the inkjet heads 2 has not been completed yet (S16: NO), the Y stage 41 is moved in the paper transport direction under the control of the Y direction movement control unit 78 ( S17). More specifically, as shown in FIG. 2, the wiping unit 40 located in the vicinity of the inkjet head 2 located on the most upstream side with respect to the paper conveyance direction is the inkjet that is located second from the upstream side with respect to the paper conveyance direction. The Y stage 41 is moved so as to move to the vicinity of the head 2. Thereafter, returning to step S12, the flushing operation is performed again while moving the waste ink tray 62 and the wiping unit 40 from the standby position to the initial position.

  On the other hand, when it is determined that wiping of all the inkjet heads 2 has been completed (S16: YES), the inkjet head 2 is returned to the printing position under the control of the frame position control unit 75, and the maintenance is completed.

  That is, in the present embodiment, the target heads are sequentially set from the inkjet head 2 positioned on the upstream side in the paper transport direction, and the operations of steps S12 to S15 are repeated four times, and maintenance of all the inkjet heads 2 is performed. Is done.

  As described above, in the maintenance method of the inkjet head 2 according to the present embodiment, the ink discharged from the target head is attached to the wiper 45 before the wiping step of wiping the nozzle surface 2a of the target head with the wiper 45 is performed. A liquid deposition step is performed. Therefore, even when ink of a different color from the ink discharged from the target head adheres to the wiper 45, the ink can be washed away or diluted. Therefore, when wiping is performed, it is possible to prevent ink of a color different from the ink discharged from the target head from adhering to the nozzle surface 2a of the target head from being mixed.

  In the maintenance method for the inkjet head 2 according to the present embodiment, after the wiping step is performed, the ink adhering to the wiper 45 is absorbed by the ink absorber 19. Therefore, it is possible to prevent color mixing when the next wiping is performed.

  Further, in the maintenance method for the inkjet head 2 of the present embodiment, the liquid adheres while moving the wiper 45 in the sheet conveyance direction so as to be the target head in order from the inkjet head 2 positioned on the upstream side in the sheet conveyance direction. The step and wiping step are repeated four times. Therefore, if the wiper 45 has a length corresponding to the width of one inkjet head 2 (the length along the paper transport direction), the nozzle surfaces 2a of all the inkjet heads 2 can be wiped. Therefore, the printer 1 can be reduced in size.

  In the maintenance method for the inkjet head 2 of the present embodiment, the liquid adhesion step is performed while moving the wiper 45 from the standby position to the initial position, and the wiping step is performed while moving the wiper 45 from the initial position to the standby position. Do. That is, the liquid adhesion step and the wiping step are performed during the operation of reciprocating the wiper 45 once. Therefore, the conversion of the operation from the liquid adhesion step to the wiping step can be performed smoothly.

  In the maintenance method of the inkjet head 2 according to the present embodiment, in the liquid adhering step, the actuator unit 21 is driven by the control of the ink discharge control unit 73 to perform the flushing operation, and the ink discharged from the nozzle 10 by the flushing operation. Is attached to the wiper 45. Therefore, a special mechanism for attaching ink to the wiper 45 is not required, and the ink can be easily attached to the wiper 45.

  In addition, in the maintenance method of the ink jet head 2 of the present embodiment, the flushing operation is performed in the liquid adhesion step so that ink is ejected only from the nozzles 10 arranged in the region facing the wiper 45 of the nozzle surface 2a. . Accordingly, it is possible to suppress ink consumption as compared with the case where the flushing operation is performed so that ink is ejected from all the nozzles 10.

  Furthermore, in the inkjet printer 1 of the present embodiment, the height position of the inkjet head 2 can be changed by the control of the frame position control unit 75. Therefore, even if there is no mechanism for moving the wiper 45 in the direction orthogonal to the nozzle surface 2a, the inkjet head 2 and the wiper 45 can be relatively moved in the direction orthogonal to the nozzle surface 2a. Therefore, the configuration of the printer 1 can be simplified.

  Here, a modification of the first embodiment will be described. In this modification, only the maintenance method of the first embodiment is changed, and the configuration of the printer 1 is the same as that of the first embodiment. To do.

  That is, in the liquid adhesion step in the maintenance method of the first embodiment, the ink is adhered to the wiper 45 while the wiper 45 is moved under the control of the X-direction movement control unit 77. In the liquid adhesion step, the X-direction movement control unit 77 controls the wiper 45 to be stationary in a state where the wiper 45 is in a position facing the nozzle surface 2a. Then, under the control of the ink ejection control unit 73, ink is ejected only from the nozzles 10 arranged in the region facing the wiper 45 on the nozzle surface 2a.

  As described above, in the present modification, as in the first embodiment, ink discharged from the target head can be attached to the wiper 45 before wiping, and thus color mixing can be prevented.

  Further, in this modification, the ink adhesion process is completed in a shorter time than when the wiper 45 is moved. Further, it is possible to minimize the amount of ink discharged by flushing in order to adhere ink to the wiper 45.

<Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a flowchart illustrating the operation of the printer 1 during maintenance according to the present embodiment. 12 and 13 are diagrams for explaining the movement of the inkjet head 2 and the maintenance unit 30 during the maintenance of the present embodiment.

  The main difference between the maintenance method of the present embodiment and the maintenance method of the first embodiment is that, in the first embodiment, the ink discharged from the nozzles 10 by the flushing operation before the wiping step is removed from the wiper 45. In this embodiment, however, the ink adhered to the nozzle surface 2a is adhered to the wiper 45 by the purge operation. Since the configuration of the printer 1 is the same as that of the first embodiment, the same reference numerals are given and description thereof is omitted, and the maintenance method will be described below.

  First, as shown in FIG. 12A, the inkjet head located at the printing position (position indicated by the broken line in the figure) is moved to the retracted position (S21). Further, as shown in FIG. 12B, the waste ink tray 62 and the wiping unit 40 are moved from the standby position toward the initial position (S22). Thereafter, as shown in FIG. 12C, the inkjet head 2 is moved from the retracted position to the purge position, and purge is executed (S23: purge step).

  Subsequently, as shown in FIG. 13D, the inkjet head 2 is moved to an ink adhesion position where the height position of the nozzle surface 2 a is slightly higher than the height position of the tip of the wiper 45 by the control of the frame position control unit 75. Then, the X stage 31 is moved to the standby position under the control of the X direction movement control unit 77 (S24: liquid adhesion step). Note that the difference between the height position of the nozzle surface 2a of the inkjet head 2 at the ink adhesion position and the height position of the tip of the wiper 45 is that the nozzle surface is removed by the purge operation while the tip of the wiper 45 is separated from the nozzle surface 2a. It is a grade which contacts the ink adhering to 2a. Specifically, it is about 0.5 mm. Therefore, the ink discharged from the nozzle 10 of the target head can be attached to the wiper 45 by step S24.

  Further, as shown in FIG. 13E, the X stage 31 is moved to the initial position under the control of the X direction movement control unit 77 (S25). At this time, in the previous liquid adhesion step, even if there are ink droplets that are mostly not adhered (moved) to the wiper, they will adhere to the wiper 45 by re-movement to the initial position. This ensures that the different color ink on the wiper 45 is diluted or replaced. Next, after the inkjet head 2 is moved to the wipe position, the wiping unit 40 is moved from the initial position toward the standby position as shown in FIG. Thereby, the foreign material adhering to the nozzle surface 2a of the target head is wiped off by the wiper 45 (S26: wiping step). Then, as shown in FIG. 13G, the ink absorber 19 is lowered to a position in contact with the wiper 45 to absorb the ink attached to the wiper 45 (S27).

  Subsequently, it is determined whether or not wiping of all inkjet heads 2 has been completed (S28), and if it is determined that wiping of all inkjet heads 2 has not been completed (S28: NO), the Y stage 41 is moved in the paper transport direction, and the wiping unit 40 is moved to the vicinity of the adjacent inkjet head 2 (S29). Thereafter, returning to step S22, the waste ink tray 62 and the wiping unit 40 are moved again from the standby position to the initial position. On the other hand, when it is determined that wiping of all the inkjet heads 2 has been completed (S28: YES), the inkjet head 2 is returned to the printing position and the maintenance is terminated.

  As described above, in the present embodiment, as in the first embodiment, since the ink discharged from the target head can be attached to the wiper 45 before wiping, color mixing can be prevented. .

  Further, in the present embodiment, the ink discharged by the purge operation that forcibly discharges foreign matters such as air, dust, and deteriorated ink mixed in the inkjet head 2 to the outside together with the ink in the liquid adhesion step. Since it adheres to the wiper 45, wasteful ink is not used.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various design changes can be made as long as they are described in the claims. Is.

  For example, in the first and second embodiments described above, the inkjet head 2 and the wiper 45 are moved to the nozzle surface 2a by changing the height position of the inkjet head 2 fixed to the frame 3 by the frame moving mechanism 51. However, the present invention is not limited to this, and the wiping unit 40 having the wiper 45 may be configured to be movable in the direction orthogonal to the nozzle surface 2a.

  In the first and second embodiments described above, the case where the ink absorber 19 for absorbing ink attached to the wiper 45 is provided has been described. However, the ink absorber 19 may be omitted.

  In the first embodiment described above, the liquid adhesion step is performed while moving the wiper 45 from the standby position to the initial position, and the wiping step is performed while moving the wiper 45 from the initial position to the standby position. Although described, this is not limiting. For example, in the liquid adhesion step, the wiper 45 may be moved from the initial position to the standby position as in the wiping step.

  In addition, in the first embodiment described above, the case where the flushing operation is performed so that ink is ejected only from the nozzles 10 arranged in the region facing the wiper 45 of the nozzle surface 2a in the liquid adhesion step. However, ink may be ejected from all the nozzles 10.

  In the above-described second embodiment, the case where the ink attachment operation is performed on the wiper 45 while moving the wiper 45 in the main scanning direction in the liquid attachment step has been described. However, the present invention is not limited to this. . That is, the movement in the main scanning direction is stopped in a state where the wiper 45 is in a position facing the nozzle surface 2a, and the wiper 45 is brought close to the ink adhering to the nozzle surface 2a until the tip of the wiper 45 comes into contact with the ink. An ink adhesion operation may be performed.

  In the first and second embodiments described above, the inkjet head 2 and the wiper 45 are relatively moved along the longitudinal direction of the inkjet head 2 so that the inkjet head 2 is stationary (fixed) in the longitudinal direction. This is realized by moving the wiper 45, but the relationship between this movement and stationary may be reversed.

  Furthermore, in the first embodiment described above, in the liquid adhesion step to the wiper 45, the inclination of the wiper 45 with respect to the nozzle surface 2a is the same as that in the wiping step. From the viewpoint of adhering, it may be further inclined than the inclination at the wiping step.

  In the first and second embodiments described above, the direction of relative movement of the wiper 45 with respect to the inkjet head 2 is the direction along the longitudinal direction of the inkjet head 2, but is the direction along the short direction. May be.

1 is a schematic side view showing an overall configuration of an ink jet printer according to an embodiment of the present invention. It is a schematic plan view of the principal part of the inkjet printer shown in FIG. It is a top view of the inkjet head shown in FIG. It is an enlarged view of the area | region enclosed with the dashed-dotted line of FIG. FIG. 4 is a partial cross-sectional view of the ink jet head shown in FIG. 3. It is a schematic side view of the maintenance unit shown in FIG. It is a block diagram which shows schematic structure of the control apparatus shown in FIG. 2 is a flowchart showing an operation of the printer when maintenance is performed in the ink jet printer shown in FIG. 1. It is a figure for demonstrating a motion of the inkjet head and maintenance unit at the time of the maintenance in the inkjet printer shown in FIG. It is a figure for demonstrating a motion of the inkjet head and maintenance unit at the time of a maintenance in the inkjet printer shown in FIG. 10 is a flowchart illustrating an operation of a printer during maintenance according to the second embodiment. It is a figure for demonstrating a motion of the inkjet head and a maintenance unit at the time of the maintenance (1st half) of 2nd Embodiment. It is a figure for demonstrating the motion of the inkjet head and a maintenance unit at the time of the maintenance of 2nd Embodiment (latter half).

Explanation of symbols

1 Inkjet printer (liquid ejection device)
2 Inkjet head (liquid discharge head)
2a Nozzle surface 10 Nozzle 17 Pump (pressure application mechanism)
21 Actuator unit 33 Ball screw (second moving mechanism)
34 Drive motor (second moving mechanism)
43 Ball screw (third moving mechanism)
44 Drive motor (third movement mechanism)
45 wiper 51 frame moving mechanism (first moving mechanism)
74 Purge control unit (pressure application control means)
75 Frame position control unit (first movement control means)
77 X direction movement control section (second movement control means)
78 Y direction movement control unit (third movement control means)

Claims (7)

In a liquid ejection apparatus that includes a plurality of nozzle surfaces each having a plurality of nozzles, and includes a plurality of liquid ejection heads that eject different types of liquids, and a wiper that wipes off foreign matter adhering to the nozzle surfaces. A maintenance method for a liquid discharge head,
Liquid that causes the liquid discharged by the target head to adhere to the wiper that is spaced from and opposed to the nozzle surface of the target head that is to be subjected to the wiping operation by the wiper among the plurality of liquid discharge heads An adhesion step;
After the liquid adhering step, the wiper is in a state where a part of the wiper is positioned on the target head side with respect to the nozzle surface or a state where the wiper is in contact with the nozzle surface. The target head and the wiper are relatively moved, and the target head and the wiper are relatively moved along the longitudinal direction of the target head while the wiper and the nozzle surface of the target head are opposed to each other. And a wiping step for wiping off the foreign matter adhering to the nozzle surface ,
In the liquid adhering step, the target head and the wiper are relatively moved along the longitudinal direction of the target head while the wiper and the nozzle surface of the target head are spaced apart from each other, and the target in the wiping step The wiper is disposed at an initial position at which the wiping operation with respect to the head is started, and an actuator that generates ejection energy for ejecting liquid from the nozzle until the wiper is disposed at the initial position is driven. Performing a flushing operation, causing the liquid to be ejected from all the nozzles of the target head by the flushing operation, attaching the ejected liquid to the wiper,
A maintenance method for a liquid ejection head , wherein the liquid deposition head and the wiping step are repeated as many times as the number of the liquid ejection heads, with a plurality of liquid ejection heads as the target heads in order .   2. The liquid discharge head maintenance method according to claim 1, wherein after the wiping step, the liquid adhering to the wiper is absorbed by a liquid absorbent material. 3. The maintenance method of a liquid discharge head according to claim 1, wherein in the liquid attaching step, the liquid discharge head and the wiper are relatively moved in a direction opposite to a moving direction in the wiping step. 4. The liquid deposition step according to claim 1, wherein the liquid is ejected only from the nozzle located in a region facing the wiper on the nozzle surface by driving the actuator. 5. Maintenance method of liquid discharge head. A plurality of liquid discharge heads each having a nozzle surface on which a plurality of nozzles are arranged, and discharging different types of liquid;
A wiper for wiping off foreign matter adhering to the nozzle surface;
A first moving mechanism for relatively moving the liquid discharge head and the wiper in a direction perpendicular to the nozzle surface;
A second moving mechanism for relatively moving the liquid discharge head and the wiper along the longitudinal direction of the liquid discharge head while facing the wiper and the nozzle surface;
A state in which a part of the wiper is located on the liquid ejection head side with respect to the nozzle surface and a state where the wiper is separated from the state where the wiper is separated from the nozzle surface on the side opposite to the liquid ejection head. First movement control means for controlling the driving of the first movement mechanism so as to be in any one of the states in contact with the nozzle surface;
Second movement control means for driving the second movement mechanism,
The liquid discharge head has an actuator for generating discharge energy for discharging liquid from the nozzle;
Before the control by the first movement control unit, the nozzle surface of the target head that is a target to which the wiping operation by the wiper among the plurality of liquid ejection heads is performed by the control by the second movement control unit. The wiper is moved along the longitudinal direction of the target head while being separated from the wiper, the wiper is disposed at an initial position where the wiping operation with respect to the target head is started, and the wiper is disposed at the initial position. Until the liquid is discharged from the target head by a flushing operation in which the actuator is driven to discharge the liquid from all the nozzles ,
A plurality of the liquid ejection heads are arranged along a width direction orthogonal to the longitudinal direction;
A third moving mechanism for moving the wiper along the width direction;
As a plurality of the liquid ejection head becomes the target head in order, after the nozzle surface is wiped by the wiper, that you have further a third movement control means for driving the third moving mechanism A liquid ejecting apparatus. The liquid ejection apparatus according to claim 5 , wherein the first movement mechanism moves the liquid ejection head. The liquid ejecting apparatus according to claim 5, wherein the flushing operation is performed by driving only the actuator corresponding to a region of the nozzle surface facing the moving wiper.

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