JP6003639B2 - Liquid ejection device - Google Patents

Description

  The present invention relates to a liquid ejection device that ejects liquid from ejection ports.

  The nozzle surfaces of a plurality of ink jet heads are sealed with corresponding head caps, and one suction pump is connected to the head cap in order to suck ink from the nozzles of the ink jet head. Inkjet printers are known in which the thickened ink is discharged into the head cap and the ejection performance of the inkjet head is restored. (For example, refer to Patent Document 1).

JP 2010-125746 A

  In the above-described ink jet printer, if the ink discharged into the head cap dries, the flow path from the head cap to the suction pump may be closed by the dry ink. Therefore, after the ink is discharged into the head cap, the suction pump It is necessary to continue the ink suction to discharge the ink in the head cap to a waste ink tank or the like (so-called empty suction). However, if ink suction from the nozzles of the inkjet head and idle suction of the ink discharged into the head cap are sequentially performed for a plurality of caps, the time required to recover the ejection performance of the inkjet head becomes longer.

  An object of the present invention is to provide a liquid ejection apparatus capable of shortening the time for recovering ejection performance.

The liquid ejection apparatus according to the present invention corresponds to one or a plurality of liquid ejection heads having a plurality of ejection ports for ejecting a liquid in total, and a plurality of ejection port groups each included in the plurality of ejection ports. A plurality of caps provided for sealing each discharge port group to the outside, and having a recess for forming a sealing space facing the discharge port group when sealing each discharge port group And a moving means for individually moving each of the plurality of caps relative to the one or the plurality of liquid discharge heads, each of the plurality of caps being one of the plurality of discharge port groups. A plurality of suction units each of which is connected to the recesses of the plurality of caps, and a sealing mechanism that can take a sealed state that seals one corresponding discharge port group and an unsealed state that is not sealed A suction hand for performing suction in the tube and the recess When, the suction means, separately for each of the plurality of suction tubes, and connecting means for the connection or non-connection, the sealing mechanism, and a control means for controlling said suction means and said connecting means The connecting means is an internal space formed inside, and a hole formed in the outer surface, each having a plurality of communication holes communicating with the internal space; and the internal A rotating body housed in the space and rotatable along the inner surface of the housing defining the internal space, and the plurality of suction pipes are connected to the corresponding communication holes, respectively. The rotating body rotates in the internal space in a predetermined direction so that the suction means has two communication holes to which the plurality of suction pipes of the plurality of communication holes are connected. Only one, both of the two communication holes, and the front Only the other two communication holes and order are formed internal passage so as to communicate with each other, wherein the control means controls the connecting means so as to rotate the rotating body (a) the predetermined direction (B) The plurality of caps connected to the one of the two communication holes through one of the plurality of suction pipes in a state where only one of the suction means and the two communication holes communicates. to the one first and sealed state, to control the sealing mechanism, (c) in a state that both of the suction means and the two communication holes communicating said plurality of said one of said two communication holes cormorant by a non-sealed state said one of the plurality of cap the is connected through one of the suction pipe, and another one of the previous SL plurality of suction tubes to the other of the two communication holes Another one of the plurality of caps connected through one of the One to the sealing state, the controls sealing mechanism, (d) the state in which only the other is communicated to the suction means and the two communication holes, the plurality of the other of the two communication holes to maintain the single one said another of the plurality of caps being connected through said other one of the suction pipe in the sealing state, to control the sealing mechanism, and (e) said suction means, said Only one of the two communication holes, both of the two communication holes, and only the other of the two communication holes are in communication with each other, and the one of the plurality of suction pipes is connected to the two communication holes. and controlling said suction means to draw said one and said another one of said recesses of said plurality of caps that are connected through the another one.

According to the present invention, the liquid remaining in one recess of the plurality of caps in the non-sealed state is sucked, and at the same time, the pressure in the other one recess of the plurality of caps in the sealed state is made negative. Since the liquid can be purged from the discharge port, the maintenance operation of the discharge port can be completed quickly.

1 is a schematic side view showing the inside of an ink jet printer according to a first embodiment of the present invention. It is a schematic block diagram of the maintenance unit shown in FIG. It is a schematic sectional drawing of the rotary valve shown in FIG. It is a figure which shows the hardware constitutions of the control apparatus shown in FIG. It is a functional block diagram of the control apparatus shown in FIG. FIG. 2 is a flowchart when performing maintenance work for the printer shown in FIG. 1. FIG. It is a figure for demonstrating operation | movement of the maintenance unit shown in FIG. It is a figure for demonstrating operation | movement of the maintenance unit shown in FIG. It is a timing chart which shows operation | movement of the maintenance unit shown in FIG. It is a schematic sectional drawing of the rotary valve of 2nd Embodiment. It is a figure for demonstrating operation | movement of the rotary valve shown in FIG. It is a figure for demonstrating the modification of this embodiment. It is a figure for demonstrating the further modification of this embodiment. It is a figure for demonstrating the further modification of this embodiment.

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

<First Embodiment>
First, a schematic configuration of the ink jet printer 1 according to the first embodiment of the present invention will be described.

  As shown in FIG. 1A, the printer 1 has an upper casing 11 and a lower casing 12 that are both rectangular parallelepiped. In addition, the left side surface in FIG. In addition, the right side surface in FIG. The upper housing 11 has an open bottom surface, and the lower housing 12 has an open top surface. The upper housing 11 is connected to the lower housing 12 so as to be rotatable about a rotation shaft 13. The upper housing 11 rotates between a closed position that seals the opening surfaces of each other and defines the internal space of the printer 1 and an open position that is a position that opens the internal space of the printer 1. . An open / close sensor 16 is fixed to the upper surface of the lower housing 11. The open / close sensor 16 is configured to output a detection signal when the upper casing 11 is in the closed position and not to output a detection signal when the upper casing 11 is in the open position. The printer 1 has a lock mechanism 14 that restricts rotation of the upper casing 11 when the upper casing 11 is in the closed position. A paper discharge unit 15 is provided on the upper surface of the upper housing 11. The paper P that has been printed is sequentially discharged to the paper discharge unit 15.

  Further, in the internal space of the printer 1, six inkjet heads 2, a paper tray 20, a paper transport mechanism 30, a platen 9, and a maintenance unit 40 are arranged.

  As shown in FIG. 1B, it has a substantially rectangular parallelepiped shape, and has an ejection surface 2a on the lower surface of which a plurality of ejection ports 8 for ejecting ink droplets are formed. Ink is supplied from an ink tank (not shown). The ink supplied to the inkjet head 2 reaches the ejection port 8 via a common ink chamber and a plurality of pressure chambers communicating with the common ink chamber. Inside the inkjet head 2, an actuator (not shown) that applies pressure to the ink stored in the pressure chamber is disposed. By driving the actuator, ink droplets are ejected from the ejection port 8.

  The six inkjet heads are arranged in the order of yellow, light cyan, light magenta, cyan, magenta, and black from the upstream side in the transport direction of the paper P. In the present embodiment, each inkjet head 2 has a configuration corresponding to one different type of ink, but a plurality of inkjet heads 2 may correspond to one ink type, or one inkjet head 2. May correspond to a plurality of ink types.

  The sheet tray 20 can hold a plurality of stacked sheets P and is detachably disposed on the bottom surface of the lower housing 12.

  The platen 9 is a plate member for supporting paper, and is fixed to the lower housing 12 so as to face the ejection surface 2a of the inkjet head 2 when the upper housing 11 is in the closed position. The sizes of the platen 9 in the main scanning direction and the sub-scanning direction are slightly larger than the ejection surfaces 2 a related to the six inkjet heads 2.

  The paper transport mechanism 30 constitutes a transport path for the paper P passing from the paper tray 20 through the six inkjet heads 2 and the platen 9 to the paper discharge unit 15. The paper transport mechanism 30 includes a pickup roller 31, nip rollers 32a to 32e, and guides 33a to 33d. The pickup roller 31 sends out the sheets P stacked on the sheet tray 20 one by one from above. The nip rollers 32 a to 32 e are arranged along the conveyance path and apply a conveyance force to the paper P. The guides 33a to 33d are respectively disposed between the pickup roller 31 and the nip rollers 32a to 32e in the conveyance path, and the sheet P to which conveyance force is applied by the nip rollers 32a to 32e reaches the next nip rollers 32a to 32e. The paper P is guided. When the paper P transported by the paper transport mechanism 30 passes between the six ink jet heads 2 and the platen 9, an image is formed by ink droplets ejected from the ejection surface (ejection port 8) 2 a of each ink jet head 2. Is printed. The paper P on which the image is printed is further transported by the paper transport mechanism 30 and discharged to the paper discharge unit 15.

  As shown in FIGS. 1 and 2, the maintenance unit 40 performs a maintenance operation for recovering clogging of the discharge ports 8 of the inkjet head 2. The maintenance operation includes a purge operation for forcibly discharging ink from the ejection port 8. The maintenance unit 40 includes six cap members 41, an elevating mechanism 42, six suction pipes 43, a pump 44, a waste liquid pipe 45, a rotary valve 46, and a waste liquid tank 51.

  The six cap members 41 are elastic members that seal the discharge ports 8 of the corresponding inkjet heads 2 to the outside, and are formed with concave portions 41a that open upward so as to surround the discharge surface 2a. When the tip of the annular projection defining the recess 41a comes into contact with the ejection surface 2a, all the ejection ports 8 of the corresponding inkjet head 2 are sealed from the outside (disposed on the far left in FIG. 2). 2), and when the tip is separated from the discharge surface 2a, the discharge port 8 is opened to the outside (unsealed state: the cap member arranged on the leftmost in FIG. 2) Other cap members 41 except 41).

  The elevating mechanism 42 supports the six cap members 41 arranged in one direction. Although detailed description is omitted, the elevating mechanism 42 is provided on the discharge surface 2a facing each cap member 41 so that each of the six cap members 41 supported is independently sealed or opened. It is possible to move up and down. When the printer 1 is in a print standby state, the elevating mechanism 42 is retracted in the back direction of FIG. 1 of the platen 9 so as not to face the ejection surface 2a. When performing the maintenance operation, the elevating mechanism 42 moves to a maintenance position where each cap member 41 faces the corresponding discharge surface 2a by a moving mechanism (not shown). The maintenance operation includes an operation of sealing the discharge surface 2a with the cap member 41 to prevent the discharge port from being dried, in addition to the purge operation.

  The pump 44 is for performing suction in the recess 41 a of the cap member 41. The rotary valve 46 is a valve for communicating one or two of the six cap members 41 with the pump 44. The waste liquid tank 51 stores the waste ink discharged from the ejection port 8 of the inkjet head 2. Waste ink is generated by a purge operation for forcibly discharging a large amount of ink from the ejection port 8 or a flushing operation for ejecting ink droplets from the ejection port 8. The six suction pipes 43 are connected to the corresponding recesses 41a of the cap member 41 and the rotary valve 46, respectively. The waste liquid pipe 45 is connected to the rotary valve 46 and the waste liquid tank 51. A pump 44 that generates a suction force is connected to the waste liquid pipe 45.

  The rotary valve 46 will be described in detail with reference to FIGS. 2 and 3. As shown in FIGS. 2 and 3, the rotary valve 46 has a cylindrical housing 55 and a cylindrical shape that is housed in the internal space 55 b of the housing 55 and is rotatable in the circumferential direction in the internal space 55 b. And a rotating body 56 having The casing 55 is formed with seven communication holes 55a that allow the internal space 55b to communicate with the outside. Among the seven communication holes 55a, six communication holes 55a arranged along the circumferential direction on the outer peripheral surface of the housing 55 are ports A to F, and are formed at the center of the end surface of the housing 55. The hole 55a is a port G. A suction pipe 43 is connected to the ports A to F, and a waste liquid pipe 45 is connected to the port G.

  The rotating body 56 includes first and second flow paths 56a and 56b extending along the radial direction from the outer peripheral surface to the rotation axis, and the first and second flow paths extending along the rotation axis. A third flow path 56c that connects the paths 56a, 56b and the port G is formed. The width of the second flow path 56b in the circumferential direction becomes wider toward the outer peripheral surface. Thereby, the flow path cross-sectional area of the first flow path 56a becomes smaller than the flow path cross-sectional area of the second flow path 56b. The first and second flow paths 56a and 56b are configured such that, when the rotating body 56 rotates in one direction, only one of the two ports A to F adjacent to each other among the ports A to F and the two ports A to F. Both F and the other of the two ports A to F are sequentially communicated with each other. As will be described later, the first flow path 56a is connected to the ports A to F corresponding to the recessed portion 41a in the open state, and the second flow path 56b is connected to the ports A to F corresponding to the recessed portion 41a in the sealed state. Connected to. At this time, the recess 41a corresponding to the ports A to F to which the first and second flow paths 56a and 56b are connected and the port G (with the pump 44) are connected. The rotational position of the rotator 56 is controlled by a motor (not shown).

  Next, the control device 1p that controls the printer 1 will be described. As shown in FIG. 4, the control device 1p includes a CPU (Central Processing Unit) 71, an EEPROM (Electrically Erasable and Programmable Read Only Memory) that stores a program executed by the CPU and data used in these programs in a rewritable manner. ) 72, a RAM (Random Access Memory) 73 that temporarily stores data during program execution, an I / F circuit 74 that communicates with an external PC 90, etc., a touch panel 76, and various sensors (not shown) I / O circuit 75 is included. These are connected to each other via a data bus 81. Each functional unit of the control device 1p described later is constructed by cooperation of these hardware and software in the EEPROM.

  As illustrated in FIG. 5, the control device 1 p includes a print control unit 61, a maintenance control unit 62, and a display control unit 63. The print control unit 71 controls the operations of the inkjet head 2 and the paper transport mechanism 30 so that a desired image is printed on the paper P. The display control unit 63 controls the touch panel 76. The maintenance control unit 62 controls the elevating mechanism 42, the rotary valve 46, and the pump 44 so that a maintenance operation including a purge operation is executed. The purge operation includes a suction operation that sucks only the inside of the recessed portion 41a of one cap member 41 that is in a sealed state, an empty suction operation that sucks the inside of the recessed portion 41a of the cap member 41 that is open, And a pre-suction operation for sucking the inside of the recess 41a of the other cap member 41 that is in a sealed state simultaneously with the suction operation.

  The purge operation among the maintenance operations performed by the maintenance control unit 62 will be described in detail with reference to FIGS. As shown in FIG. 6, when the purge operation is started, the maintenance control unit 62 causes the concave portions 41 a of the cap member 41 and the ejection surface 2 a of the inkjet head 2 corresponding to the cap member 41 to face each other. The elevating mechanism 42 is moved to (S101), and the elevating mechanism 42 is controlled so that all the cap members 41 are in a sealed state (S102). Thereby, it can prevent that the discharge outlet 8 is sealed and dried. Then, the maintenance control unit 62 performs the suction operation with respect to the ink jet head 2 corresponding to the port A, and as illustrated in FIG. 7A, the maintenance body 62 rotates the rotating body 56 to connect the port A and the second flow path 56b. Connecting. Thereby, the recessed part 41a of the cap member 41 in the sealed state corresponding to the port A and the pump 44 communicate with each other. In this state, the suction operation is executed by driving the pump 44 for a predetermined time, and the ink is purged into the concave portion 41a from the ejection port 8 of the inkjet head 2 sealed by the concave portion 41a (S103).

  Next, the maintenance control unit 62 opens the cap member 41 corresponding to the inkjet head 2 that has previously performed the suction operation, and performs an empty suction operation to suck the ink accumulated in the recess 41a, and then performs a suction operation. A pre-suction operation is performed simultaneously with the cap member 41 corresponding to the inkjet head 2 in a sealed state to suck the recess 41a in advance (S104). Specifically, the maintenance control unit 62 shifts the cap member 41 corresponding to the port A from the sealed state to the open state, and the cap member 41 corresponding to the port B is maintained in the sealed state. Thus, the lifting mechanism 42 is controlled (first sealing state). Further, as shown in FIG. 7B, the maintenance control unit 62 rotates the rotating body 56 counterclockwise so that the port A and the first flow path 56a are connected, and the port B and the second flow path 56b are respectively set. Connect (first connection state). As a result, the recesses 41a of the two cap members 41 corresponding to the ports A and B communicate with the pump 44 being sucked, and the empty suction operation is performed on the recesses 41a of the open cap member 41 corresponding to the port A. A pre-suction operation is performed on the recessed portion 41a of the sealed cap member 41 corresponding to the port B.

  The maintenance control unit 62 waits until the elapsed time from the start of the idle suction operation reaches the time t1 (S105: NO). This time t1 is equal to or longer than the time required to suck the entire amount of the maximum amount of ink that can be stored in the recess 41a of the cap member 41 that is the target of the idle suction operation. Thereby, the ink remaining in the recess 41a can be reliably discharged. At this time, as shown in FIG. 9, while the ink remaining in the recess 41a corresponding to the port A is being sucked by the idle suction operation, the internal pressure of the recess 41a corresponding to the port A and the port B decreases. Thereafter, when all of the ink remaining in the recess 41a corresponding to the port A is sucked, the port A is released to the atmosphere, so that the internal pressure of the recess 41a corresponding to the port A and the port B increases. However, a certain level of negative pressure is maintained as the pump 44 continues to suck.

  When the maintenance control unit 62 determines that the elapsed time has reached the time t1 (S105: YES), the maintenance control unit 62 determines whether or not the idle suction operation has been completed for all the inkjet heads 2 (S106). When the maintenance control unit 62 determines that the idle suction operation has been completed for all the inkjet heads 2 (S106: YES), the maintenance control unit 62 opens all the cap members 41 (S109), and then moves the elevating mechanism 42 to the ejection surface. It retracts to a position not facing 2a, and the flowchart of FIG. 6 is terminated (S110).

  When it is determined that the idle suction operation has not been completed for all the inkjet heads 2 (S106: NO), the maintenance control unit 62 continues the purge operation for the next inkjet head 2 (S107). First, the maintenance control unit 62 moves up and down so that the cap member 41 corresponding to the port A shifts from the open state to the sealed state, and the cap member 41 corresponding to the port B is maintained in the sealed state. As shown in FIG. 7C, the mechanism 42 is controlled to rotate the rotator 56 counterclockwise to block the port A while maintaining the connection between the port B and the second flow path 56b (first). 2 connection state). As a result, only the recessed portion 41a of the cap member 41 in the sealed state corresponding to the port B communicates with the pump 44 being driven, the suction operation is started, and the discharge of the inkjet head 2 sealed by the recessed portion 41a is started. Ink is purged from the outlet 8. At this time, as shown in FIG. 9, the pressure in the recess 41 a corresponding to the port B is maintained at the negative pressure by the previously performed pre-suction operation. The negative pressure can be quickly reduced to a desired pressure as compared with the broken line). Thereby, the ink can be efficiently purged from the ejection port 8 of the inkjet head 2 sealed by the concave portion 41a. Then, the maintenance control unit 62 stands by until the elapsed time from the start of the suction operation reaches the time t2 (S108: NO). The time t2 corresponds to a time during which the discharge performance of the discharge port 8 of the inkjet head 2 can be recovered by purging.

  When the maintenance control unit 62 determines that the elapsed time has reached the time t2 (S108: YES), according to the above-described processing, the purge operation should be performed at the same time as performing the idle suction operation for the recess 41a where the suction operation has been performed. If there is a next inkjet head 2, a pre-suction operation is performed on the recess 41 a corresponding to the inkjet head 2. Thereafter, the same processing is repeated between the ports B and C, between the ports C and D, between the ports D and E, and between the ports E and F (see FIGS. 8A and 8B). The pre-suction operation, the suction operation, and the idle suction operation are sequentially executed for each corresponding inkjet head 2. As shown in FIG. 8C, the idle suction operation is performed independently for the inkjet head 2 corresponding to the port F (S104). In the present embodiment, when the idle suction operation is completed for the inkjet head 2 corresponding to the port F, it is determined that the idle suction operation has been completed for all the inkjet heads 2 (S106: YES), and the maintenance control unit 62 After all the cap members 41 are opened (S109), the elevating mechanism 42 is retracted to a position not facing the ejection surface 2a, and the flowchart of FIG. 6 is ended (S110).

  As described above, according to the printer 1 according to the present embodiment, by performing suction in the first connected state, the pre-suction that makes the inside of the concave portion 41a of the cap member 41 that is the target of the suction operation negative pressure simultaneously with the idle suction operation. The action can be performed. Thereby, the maintenance operation can be completed quickly. Also, by switching from the pre-suction operation to the suction operation in this state, the pressure in the recess 41a can be quickly reduced to a predetermined negative pressure compared to the case where the interior of the recess 41a is not previously negative. Can do. Thereby, the ink can be efficiently purged, and the time for recovering the ejection performance can be shortened.

  Further, the time t1 for continuing the idle suction operation is equal to or longer than the time necessary for suctioning the entire amount of the maximum amount of ink that can be stored in the concave portion 41a of the cap member 41 that is the subject of the idle suction operation. The ink remaining in the recess 41a can be reliably discharged.

  Furthermore, by using the rotary valve 46, it is possible to easily change the connection between the six suction pipes and the waste liquid pipe and to reduce the size.

  In the rotating body 56 of the rotary valve 46, the flow passage cross-sectional area of the first flow passage 56a is smaller than the flow passage cross-sectional area of the second flow passage 56b. The pressure of the recessed part 41a which connects can be made into a negative pressure efficiently.

  Since all the other cap members 41 that are not performing the pre-suction operation, the suction operation, and the idle suction operation are in the sealed state, the discharge port 8 can be prevented from drying.

Second Embodiment
A second embodiment of the present invention will be described with reference to FIGS. Since only the rotary valve 146 is different from the first embodiment in the second embodiment, only the configuration and operation of the rotary valve 146 will be described below. Other members and functional units are denoted by the same reference numerals as those in the first embodiment, and description thereof is omitted.

  The rotary valve 146 includes a casing 55 having a cylindrical shape, and a rotating body 56 having a cylindrical shape that is housed in the inner space 55b of the casing 55 and is rotatable along the circumferential direction in the inner space 55b. Yes. The casing 55 is formed with seven communication holes 55a that allow the internal space 55b to communicate with the outside. Among the seven communication holes 55 a, six communication holes 55 a that are equally arranged at a central angle of 60 degrees along the circumferential direction on the outer peripheral surface of the housing 55 are ports A to F, and the end surface of the housing 55 A communication hole 55 a formed at the center of the port is a port G. A suction pipe 43 is connected to the ports A to F, and a waste liquid pipe 45 is connected to the port G.

  The rotating body 56 has six communication channels 156aa, 156ab, 156ba, 156bb, 156ca, 156cb extending along the radial direction from the outer peripheral surface to the rotation axis, and extending along the rotation axis, A communication flow path 156d that connects the communication path 156aa, 156ab, 156ba, 156bb, 156ca, 156cb and the port G is formed. The communication channels 156aa and 156ab, the communication channels 156ba and 156bb, and the communication channels 156ca and 156cb are paired. The communication channels 156aa and 156ab are separated by a central angle of 60 degrees with respect to the circumferential direction, the communication channels 156ba and 156bb are separated by a central angle of 120 degrees with respect to the circumferential direction, and the communication channels 156ca and 156cb are separated from each other. They are separated by a central angle of 180 degrees in the circumferential direction. As for communication channel 156aa, 156ab; 156ba, 156bb; 156ca, 156cb, the width about the peripheral direction has spread in the direction separated from the other communication channel used as a pair, as it goes to an outer peripheral surface. Further, the communication channels 156aa, 156ab; 156ba, 156bb; 156ca, 156cb which are different from each other are separated from each other by an angle other than the central angle of 60 degrees with respect to the circumferential direction.

  The communication flow paths 156aa, 156ab; 156ba, 156bb; 156ca, 156cb are obtained by rotating the rotator 56 in one direction, so that only one of the two ports A-F arbitrarily selected from the ports A-F, Both the two ports A to F and only the other of the two ports A to F are sequentially communicated with each other. Since the ports A to F are equally arranged every 60 degrees of the central angle, even if any two are selected, the selected two ports A to F are any of the central angles of 60 degrees, 120 degrees, and 180 degrees. Are separated from each other by any distance, and can be connected to each other by any pair of communication flow paths 156aa, 156ab; 156ba, 156bb; 156ca, 156cb. At this time, the communication channels 156aa, 156ab; 156ba, 156bb; 156ca, 156cb that are different from each other are separated from each other at an angle other than the central angle 60 degrees with respect to the circumferential direction. 156ab; 156ba, 156bb; 156ca, 156cb are not connected to the other ports AF.

  For example, as shown in FIG. 10 (a), when the port A and the port D that are separated by a central angle of 180 degrees are communicated with the pump 44, a communication flow path that is a pair separated by a central angle of 180 degrees. 156 ca and 156 cb are connected to port A and port D. In FIG. 10A, the communication channel 156ca is connected to the port A, and the communication channel 156cb is connected to the port D. Further, as shown in FIG. 10B, when the port A and the port E separated by a central angle of 120 degrees are communicated with the pump 44, a communication channel that is a pair separated by a central angle of 120 degrees. 156ba and 156bb are connected to port A and port E. In FIG. 10B, the communication channel 156bb is connected to the port A, and the communication channel 156ba is connected to the port E. Further, when the port A and the port B separated by the central angle 60 degrees are communicated with the pump 44, the communication channels 156aa and 156ab which are pairs separated by the central angle 60 degrees are connected to the ports A and B. Connecting. In FIG. 11B, the communication channel 156aa is connected to the port A, and the communication channel 156ab is connected to the port B.

  In the present embodiment, the purge operation is executed for every two ink jet heads 2 that are arbitrarily selected. For example, when the two inkjet heads 2 selected as the target of the purge operation correspond to the port A and the port B, the maintenance control unit lifts the elevating mechanism 42 so that the cap member 41 corresponding to the port B is in a sealed state. To control. Then, as shown in FIG. 11A, the maintenance control unit rotates the rotating body 56 so that only the port B communicates with the pump 44 and the other ports A and C to F are shut off. Only the communication channel 156ab is connected to the port B. At this time, the communication channel 156aa is arranged on the opposite side of the port A in the clockwise direction. Thereby, the recessed part 41a of the cap member 41 in the sealed state corresponding to the port B and the pump 44 communicate with each other. In this state, the suction operation is executed by driving the pump 44 for a predetermined time, and ink is purged into the recess 41a from the ejection port 8 of the inkjet head 2 sealed by the recess 41a.

  Further, the maintenance control unit moves the elevating mechanism 42 so that the cap member 41 corresponding to the port B shifts from the sealed state to the open state, and the cap member 41 corresponding to the port A enters the sealed state. Control (first sealing state). As shown in FIG. 11B, the maintenance control unit rotates the rotating body 56 clockwise to connect the port A and the communication channel 156aa, and connect the port B and the communication channel 156ab, respectively (first Connection Status). Thereby, the concave portions 41a of the two cap members 41 corresponding to the port A and the port B communicate with the pump 44 being sucked, and the empty suction operation is performed on the concave portion 41a of the open cap member 41 corresponding to the port B. A pre-suction operation is performed on the recessed portion 41a of the sealed cap member 41 corresponding to the port A.

  The maintenance control unit waits until an elapsed time from the start of the idle suction operation reaches a time t1 '. The time t1 'is equal to or shorter than the time necessary for sucking the entire amount of the maximum amount of ink that can be stored in the recess 41a of the cap member 41 that is the target of the idle suction operation. Thereby, while the ink remaining in the recess 41a corresponding to the port B is being sucked by the idle suction operation, the internal pressure of the recess 41a corresponding to the port A and the port B is decreased. Since the idle suction operation stops before all the ink remaining in the recess 41a corresponding to the port B is sucked, the negative pressure in the recess 41a is maintained (see FIG. 9).

  When the maintenance control unit determines that the elapsed time has reached time t1, the maintenance control unit controls the elevating mechanism 42 so that the cap members 41 corresponding to the ports A and B are in the sealed state, as shown in FIG. In addition, the port A and the communication flow path 156aa are connected while the rotation body 56 is rotated clockwise to block the port B. As a result, only the concave portion 41a of the cap member 41 in the sealed state corresponding to the port A communicates with the pump 44 being driven, the suction operation is started, and the discharge of the inkjet head 2 sealed by the concave portion 41a is started. Ink is purged from the outlet 8. At this time, since the negative pressure is maintained in the recess 41a corresponding to the port A by the pre-suction operation previously performed, the pressure is quickly reduced to the desired pressure as compared with the case where the pre-suction operation is not performed. Pressure. Thereby, the ink can be efficiently purged from the ejection port 8 of the inkjet head 2 sealed by the concave portion 41a.

  Thereafter, when the elapsed time from the start of the suction operation reaches time t2, the maintenance control unit switches from the suction operation to the idle suction operation, so that the cap member 41 shifts from the sealed state to the open state. The elevating mechanism 42 is controlled. At this time, since only the port A corresponding to the inkjet head 2 that is the target of the idle suction operation is in communication with the pump 44, the ink remaining in the recess 41a can be efficiently suctioned. The maintenance control unit stops driving the pump 44 after a predetermined time for completing the suction of the remaining ink after the idle suction operation is started, and after opening all the cap members 41, the lifting mechanism The purge operation is completed by retracting 42 to a position not facing the ejection surface 2a.

  As described above, according to the printer according to the present embodiment, by performing suction in the first connection state, the pre-suction operation that creates a negative pressure in the concave portion 41a of the cap member 41 that is the target of the suction operation simultaneously with the idle suction operation. Can be executed. Thereby, the maintenance operation can be completed quickly. Also, by switching from the pre-suction operation to the suction operation in this state, the pressure in the recess 41a can be quickly reduced to a predetermined negative pressure compared to the case where the interior of the recess 41a is not previously negative. Can do. Thereby, the ink can be efficiently purged, and the time for recovering the ejection performance can be shortened.

  Further, the time t1 ′ for continuing the idle suction operation is equal to or less than the time necessary for sucking the maximum amount of ink that can be stored in the concave portion 41a of the cap member 41 that is the target of the idle suction operation. The negative pressure in the recess 41a can be maintained in the suction operation.

  Furthermore, since only the port A corresponding to the inkjet head 2 that is the target of the idle suction operation communicates with the pump 44, the ink remaining in the recess 41a can be efficiently suctioned.

  Further, since the purge operation can be executed for two arbitrarily selected ink jet heads 2, the purge operation can be efficiently executed as necessary to reduce ink consumption.

<Modification>
In the above-described embodiment, the cap member 41 is brought into a sealed state by bringing the tip of the cap member 41 into contact with the discharge surface 2a, and the cap member 41 is brought into an open state by separating the tip from the discharge surface 2a. However, the present invention is not limited to such a configuration, and the sealed state and the open state may be switched with another configuration. For example, as shown in FIG. 12, an atmosphere communication channel 241b communicating with the atmosphere may be formed on the side wall of the cap member 41, and a valve 246b for opening and closing the atmosphere communication channel 241b may be further provided. According to this, the sealing state and the open state can be quickly switched by opening and closing the valve 246b in a state where the cap member 41 is in contact with the discharge surface 2a.

<Modification 2>
Alternatively, as shown in FIG. 13, an air communication hole 355 a is formed in the vicinity of each communication hole 55 a on the outer peripheral surface of the housing 355 of the rotary valve 346, and the first flow path 56 a and the air communication are provided in the rotating body 356. An air communication channel 356c that connects the hole 355a may be formed. According to this, even when the cap member 41 is in contact with the ejection surface 2a, the concave portion 41a connected to the communication hole 55a can always be opened, so that the control is simplified. Further, by making the flow passage cross-sectional area of the air communication hole 355a smaller than the sum of the flow passage cross-sectional areas of the suction pipes 43, the suction efficiency can be increased in the pre-suction operation.

<Modification 3>
In the above-described embodiment, each inkjet head 2 is configured to eject different types of ink droplets, but the number of inkjet heads and the number of types of ejected ink droplets do not need to match. For example, as shown in FIG. 14A, one inkjet head 502 may be configured to eject six types of ink droplets. In this configuration, six ejection port group blocks (including ejection ports 8) are arranged in the longitudinal direction of the head, and each ejection port group block 509 has an ejection port array corresponding to each type of ink. As shown in FIG. 14B, the cap member 41 seals the discharge ports 8 belonging to the corresponding discharge port group block 509. Here, the cap members 41 are arranged in the sub-scanning direction in the above configuration, but in this configuration, the cap members 41 are arranged in the main scanning direction.

  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 modifications can be made as long as they are described in the claims. For example, in the above-described embodiment, the rotating body 56 is configured to be rotatable along the circumferential direction in the internal space 55b while being accommodated in the internal space 55b having the cylindrical shape of the housing 55. As long as the body is rotatable, the shape of the internal space of the housing may be arbitrary. For example, the spherical rotating body may be configured to be rotatable in a spherical internal space.

  In the first embodiment described above, in the rotating body 56 of the rotary valve 46, the flow path cross-sectional area of the first flow path 56a is smaller than the flow path cross-sectional area of the second flow path 56b. The channel cross-sectional area of the first channel 56a may be greater than or equal to the channel cross-sectional area of the second channel 56b.

  Moreover, the width | variety regarding the circumferential direction becomes wide as each 2nd flow path of the rotary body 56 which concerns on the above-mentioned 1st embodiment, and each communicating flow path of the rotary body 56 which concerns on the above-mentioned 2nd embodiment goes to an outer peripheral surface. Although it is a structure, the shape of each flow path may be arbitrary. For example, it may extend with a uniform width.

  Furthermore, although the ports A to F of the first and second embodiments described above are arranged along the outer peripheral surface of the housing 55, the positional relationship between the ports A to F may be arbitrary. For example, any of the ports A to F may be arranged at different positions with respect to the direction orthogonal to the circumferential direction.

  In the first embodiment described above, the time t1 is equal to or longer than the time required to suck the entire amount of the maximum amount of ink that can be stored in the recess 41a of the cap member 41 that is the target of the idle suction operation. Further, the total amount of ink existing in the suction tube 43 and the waste liquid tube 45 may be longer than the time necessary for suction. If ink remains in the suction pipe 43 or the waste liquid pipe 45 during suction, the ink may adhere to the suction pipe 43 or the waste liquid pipe 45 and close as time passes. By setting the time required to suck the entire amount of ink present, the suction pipe 43 and the waste liquid pipe 45 can be prevented from being blocked.

In the first embodiment described above, the control device 1p includes a CPU (Central Processing Unit) 71. However, the control device 1p may be composed of one CPU 71 or a plurality of CPUs 71. May be. Furthermore, one or more CPUs 71 and an ASIC (Application Specific Integrated Circuit) may be combined.

  The present invention is not limited to a printer, but can be applied to a facsimile, a copier, and the like. The head may eject any liquid other than ink. The recording medium is not limited to the paper P and may be any recordable medium.

1: Inkjet printer 1p: Control device 2: Inkjet head 2a: Discharge surface 40: Maintenance unit 41: Cap member 41a: Recess 42: Lifting mechanism 43: Suction pipe 44: Pump 45: Waste liquid pipe 46: Rotary valve 51: Waste liquid Tank 55: Housing 55a: Communication hole 55b: Internal space 56: Rotating body 56a: First flow path 56b: Second flow path 56c: Third flow path 62: Maintenance control unit 146: Rotary valve 156aa: Communication flow path 156ab : Communication channel 156ba: communication channel 156bb: communication channel 156ca: communication channel 156cb: communication channel 156d: communication channel 241b: atmosphere communication channel 246b: valve

Claims (6)

One or a plurality of liquid discharge heads having a plurality of discharge ports for discharging liquid in total ;
Each of the discharge ports is provided to seal the discharge port group with respect to the outside corresponding to the plurality of discharge port groups included in the plurality of discharge ports, and when the discharge port group is sealed, the discharge port A plurality of caps each having a recess for forming a sealed space facing the group ; and a moving means for individually moving each of the plurality of caps relative to the one or the plurality of liquid ejection heads. Each of the plurality of caps includes a sealing state that seals a corresponding one of the plurality of discharge port groups and a non-sealed state that is not sealed. Mechanism ,
A plurality of suction tubes each connected to the recesses of the plurality of caps;
Suction means for performing suction in the recess;
Connection means for connecting or disconnecting the suction means individually to each of the plurality of suction pipes;
The sealing mechanism, and a control means for controlling said suction means and said connection means,
The connecting means includes
An internal space formed inside, and a hole formed in the outer surface, each having a plurality of communication holes communicating with the internal space, and
A rotating body housed in the internal space and rotatable along the inner surface of the housing that defines the internal space;
The plurality of suction pipes are connected to the corresponding communication holes, respectively.
The rotating body rotates in the internal space in a predetermined direction so that the suction means has only one of the two communication holes to which the plurality of suction pipes of the plurality of communication holes are connected. The internal flow path is formed so as to communicate with both of the two communication holes and only the other of the two communication holes in order,
The control means includes
(A) controlling the connecting means to rotate the rotating body in the predetermined direction;
(B) One of the plurality of caps connected to the one of the two communication holes through one of the plurality of suction pipes in a state where only one of the suction means and the two communication holes communicates. Controlling the sealing mechanism so that one is in a sealed state,
(C) The plurality of caps connected to the one of the two communication holes through the one of the plurality of suction pipes in a state where both the suction means and the two communication holes communicate with each other. cormorant by the two first and non-sealed state, and, sealing a different one of the plurality of caps being connected through another one of the other prior Symbol plurality of suction tubes of the two communication holes Controlling the sealing mechanism to stop,
(D) In a state where only the other of the suction means and the two communication holes communicates, the plurality of the plurality of suction pipes connected to the other of the two communication holes through the other one of the plurality of suction pipes to maintain said other one one cap sealed state, to control the sealing mechanism,
(E) In each state where only one of the suction means and the two communication holes, both of the two communication holes, and only the other of the two communication holes communicate with each other, the controller controls the suction means to draw said one and said one and said another one of said recesses of said plurality of caps that are connected through the another one of the suction tube A liquid ejecting apparatus.   Each of the plurality of caps is brought into a sealed state by bringing the opening edge of the recess into contact with the discharge surface on which the plurality of discharge ports are formed, and the opening edge of the recess is separated from the discharge surface. The liquid ejection device according to claim 1, wherein the liquid ejection device is in an unsealed state. Each of the caps
A communication channel that communicates the inside and the outside of the recess formed on the wall surface that defines the recess, and a valve that opens and closes the communication channel;
Each of the caps is in the sealed state by closing the valve and in the unsealed state by opening the valve in a state where the concave portion is in contact with the discharge surface. The liquid ejection device according to claim 1 . When the connecting means causes both the suction means and the two communication holes to communicate with each other, the plurality of suction pipes connected to the one of the two communication holes through the one of the plurality of suction pipes. first flow path communicating with said one of said recesses of the cap, and said another of said plurality of caps connected to the other of the two communication holes through one said other of said plurality of suction pipes The liquid discharge apparatus according to claim 1, further comprising: a second flow path that communicates with one of the recesses, and a communication flow path that communicates the first flow path with the outside. 5. The liquid ejection device according to claim 4 , wherein a flow path cross-sectional area of the communication flow path is smaller than a total flow path cross-sectional area of each of the plurality of suction pipes.   The liquid ejecting apparatus according to claim 1, wherein the control unit puts all the caps that are not sucked into the concave portion by the suction unit into the sealed state.

Images