JP6149465B2 - Liquid ejection device - Google Patents

Description

  The present invention relates to a liquid ejecting apparatus such as an ink jet recording apparatus that ejects liquid onto a recording medium.

2. Description of the Related Art Conventionally, an ink jet recording apparatus that forms an image by ejecting a liquid such as ink from a head onto a recording medium such as paper conveyed in a horizontal direction is known. On the ejection surface, which is the lower surface of the head, nozzles that are fine holes for ejecting ink droplets are formed. When an image is not formed on the paper, the wiper is moved along the ejection surface to move the ejection surface. A wiping operation for wiping may be performed.
In such an ink jet recording apparatus, after ink droplets are ejected from the lower surface of the head onto the paper, the area on the paper where the ink has permeated contracts and the paper warps, so that the paper contacts the lower surface of the head. The bottom surface may be scratched. In this case, ink droplets are not correctly ejected onto the paper, and the droplet ejection characteristics may change.
In view of this, an apparatus has been proposed in which an opening is provided in the lower surface of the head and a roller body that presses the sheet is provided in the opening so as to be able to move in and out in order to prevent the sheet from warping (see Patent Document 1). When ink is ejected to form an image on the paper, the roller body is protruded downward from the opening to press the paper. This prevents the paper after ink discharge from contacting the lower surface of the head. Further, during the wiping operation, the roller body is raised and retracted from the opening into the head. This avoids the ink adhering to the wiper from adhering to the roller body.

JP 2010-125598 A

In the conventional configuration, the roller body is raised during the wiping operation, and the roller body is lowered during the ink ejection. That is, a space corresponding to the vertical movement stroke of the roller body is required in the head, resulting in an increase in size.
An object of the present invention is to reduce the size of a liquid ejection device that retracts a roller body during a wiping operation.

  A liquid ejection apparatus includes: a head housing having a head element having a ejection surface for ejecting liquid; a transport mechanism that transports a recording medium toward the head housing; and a contact with the recording medium along a circumferential direction. A non-contact portion is formed, the contact portion protrudes and protrudes from the discharge surface around a central axis, and the non-contact portion is provided so as not to protrude from the discharge surface. One or more rotators that hold the recording medium by the abutting portion, and the rotating body have a protruding state in which the abutting portion protrudes from the ejection surface and a retracted state in which the abutting portion does not protrude from the ejection surface. As described above, the rotation mechanism that rotates about the central axis, the wiper that moves along the discharge surface and wipes the discharge surface, and when the wiper wipes the discharge surface, the wiper Pass through the part corresponding to the rotating body of Rutoki, the rotating body and a control unit for controlling the rotating mechanism to take the retracted state.

  When the contact portion is in the protruding state, the rotating body presses the recording medium. When wiping the discharge surface with the wiper, the control unit controls the rotation mechanism so that the contact portion of the rotating body does not protrude from the discharge surface. That is, the rotating body can be switched between a state in which the contact portion protrudes from the discharge surface and a retracted state in which the contact portion does not protrude from the discharge surface by rotation about the central axis. That is, since the central axis does not move, the space corresponding to the moving stroke of the rotating body accompanying the movement of the central axis can be reduced in the head casing. As a result, the liquid ejection device can be reduced in size.

It is a figure which shows the whole structure of an inkjet recording device. (a) is a bottom view of the head, and (b) is a view of (a) seen from the A1 direction. It is a perspective view of both rotary bodies. It is the side view which looked at the rotary body of FIG. 3 from the axial direction. It is a front view of a head element. It is a front view of a detection plate. It is a figure which shows the internal structure of a one-way clutch. (a), (b), (c) is a figure which shows rotation operation | movement of a one-way clutch. (a), (b) is a front view which shows the wiping operation | movement of the discharge surface by a wiper. It is the figure which looked at the rotary body shown in FIG. 9 from the A2 direction. (a), (b) is a front view which shows flushing operation | movement. It is a block diagram of the control part of an inkjet recording device. It is the figure which looked at the head from the 2nd direction. (a), (b) is a side view which shows operation | movement of a rotary body. It is a side view which shows operation | movement of a rotary body. It is a figure which shows the modification of a rotary body.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, upper and lower indicate directions along the vertical direction. Further, an ink jet recording apparatus is illustrated as a “liquid ejecting apparatus” according to the present invention, ink is illustrated as a specific example of “liquid”, and paper is illustrated as a specific example of a recording medium. Moreover, in the following description, about the member rotating around a central axis, let a rotation direction be the front and the reverse direction be back.

FIG. 1 is a diagram showing the overall configuration of the inkjet recording apparatus 1. The inkjet recording apparatus 1 has a rectangular parallelepiped casing 10, and a tray 11 for discharging the paper P is provided on the top plate of the casing 10. In the housing 10, there are a head 4 that ejects ink onto the paper P from the top to the bottom, a transport unit 5 that transports the paper P horizontally and then sends it to the tray 11, and a paper feed unit 6 that feeds the paper P. Has been placed. A platen 3 is provided below the head 4 so as to face the head 4 and support the paper P to be conveyed in a horizontal plane. The head 4 is provided so as to be movable up and down with respect to the platen 3.
A control unit 8 that controls the operation of each mechanism and electric circuit in the housing 10 is disposed at a position where the head 4 does not interfere with the upper portion inside the housing 10. A tank 14 that stores ink to be supplied to the head 4 is disposed on the lower side inside the housing 10. The tank 14 and the head 4 are connected by a tube (not shown).
A terminal 13 to which a signal including an image recording job transmitted from an external personal computer is input is provided on the side surface of the housing 10. A signal input from the terminal 13 is transmitted to the control unit 8. On the upper surface of the housing 10, an operation panel 12 for inputting information by a user is provided.
The transport unit 5 is a mechanism for transporting the paper P in FIG. 1 from left to right, and constitutes the “transport mechanism” of the present invention. In the following description, the direction in which the paper P is conveyed on the platen 3 is referred to as a sub-scanning direction or a first direction, and a direction orthogonal to the sub-scanning direction in a horizontal plane is referred to as a main scanning direction or a second direction.

  The transport unit 5 includes first and second transport roller pairs 51 and 52 disposed on both sides of the head 4, and third to fifth transports disposed on the transport downstream side of the paper P with respect to the transport roller pair 52. The roller pair 53, 54, 55 and three guides 56, 57, 58 through which the paper P passes are configured. Between the first transport roller pair 51 and the head 4, an end detection sensor SE1 that detects the end of the transported paper P is provided. The detection signal generated by the end detection sensor SE1 is transmitted to the control unit 8. When the conveyance downstream end of the conveyed paper P is detected by the edge detection sensor SE1, ink discharge from the head 4 to the paper P is started after a predetermined time has elapsed. The sheet P to which the conveying force is applied by the first conveying roller pair 51 is conveyed while ejecting ink from the head 4. When the conveyance downstream end of the paper P is detected by the edge detection sensor SE1, the paper P passes through the edge detection sensor SE1, so after the detection and after a predetermined time has passed, the head 4 moves to the paper P. Ink ejection is started. This predetermined time corresponds to the time when the paper P is transported to the head 4 after passing the edge detection sensor SE1.

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

The head 4 is a rectangular parallelepiped line head extending in the main scanning direction (second direction), and an ejection surface 40 in which a large number of liquid ejection ports for ejecting ink are formed is formed on the lower surface of the head 4.
The paper P on which an image is recorded by the head 4 is discharged to the tray 11 by the second to fifth transport roller pairs 52, 53, 54, 55 and guides 56, 57, 58.

Below the platen 3, a plurality of horizontally arranged caps 70 are provided so as to be movable up and down with respect to the head 4. The cap 70 is a member that receives ink. When printing is performed by ejecting ink onto the paper P, the cap 70 is positioned below the transport path of the paper P so as not to interfere with the printing. Evacuated.
If the ejection surface 40 remains exposed when printing is not performed for a long time, the ink remaining on the ejection surface 40 is dried. As a countermeasure, when printing is not performed for a long time, the head 4 is lowered, the lower end portion of the head 4 is brought into contact with the cap 70 through the platen 3, and the gap between the discharge surface 40 and the upper surface of the cap 70 is set. Forming a sealed space. This prevents the ejection surface 40 from being exposed.

FIG. 2A is a bottom view of the head 4 and shows the second direction sideways. FIG.2 (b) is the figure which looked at (a) from A1 direction. That is, FIG. 2B is a left side view of the head 4 in FIG. 1 and is shown upside down. The head 4 is formed in a head housing 44 having a lower plate 42 by arranging a plurality of, in FIG. 2A, six head elements 41 in a staggered manner in the second direction. Each head element 41 has a substantially rectangular parallelepiped box shape, and the lower surface forms the discharge surface 40. A through hole 46 is formed in the lower plate 42 corresponding to the head element 41, and the ejection surface 40 of each head element 41 is fitted in the through hole 46 and protrudes downward from the lower surface of the lower plate 42. Each head element 41 is formed in the same structure in order to make the ink ejection characteristics uniform and reduce the manufacturing cost. The head 4 is formed by arranging six head elements 41 in a zigzag pattern along the second direction, but the number of head elements 41 may be 1 to 5, 7 or more. It is not necessary.
On the discharge surface 40, a plurality of discharge port arrays 45 formed by connecting a large number of discharge ports in the second direction are formed in the first direction. For convenience of illustration, the discharge port array 45 is indicated by a rectangle. In addition, although four ejection port arrays 45 are formed on each head element 41, the number of ejection port arrays 45 is not limited to four.
The head element 41 includes a flow path unit formed by laminating a plurality of metal plates and an actuator unit bonded to the upper surface of the flow path unit. When the actuator unit is energized, the flow path unit The ink inside is ejected. The lower surface of the metal plate positioned at the lowest position of the flow path unit constitutes the discharge surface 40 and the actuator unit is connected to the control unit 8, but this configuration is publicly known and will not be described in detail.

The platen 3 (see FIG. 2B) is provided with a through hole (not shown) into which the discharge surface 40 protruding from the through hole 46 is fitted. Between the platen 3 and the cap 70 (see FIG. 1), a wiper 9 for wiping the discharge surface 40 is provided so as to be movable in the second direction. The wiper 9 is formed of an elastic material extending along the first direction. After the ink is completely ejected from the head 4, the wiper 9 moves along the second direction from a state waiting on the side of the head 4. The discharge surface 40 is wiped off.
Further, the discharge port array 45 of the head element 41 may be clogged or have a discharge failure due to ink drying or foreign matter adhesion. In order to prevent this, an empty ink ejection operation that does not contribute to image formation is performed in a state where the paper P is not positioned on the platen 3 and the wiper 9 is on standby.
In this idle ejection operation, a purge operation for forcibly discharging ink from the ejection surface 40 of the head element 41, or capping ink from the head element 41 through the platen 3 while the head element 41 and the cap 70 are spaced apart from each other in the vertical direction. There is a flushing operation for discharging toward 70. The purge operation refers to suction purge or positive pressure purge. The suction purge is performed by applying a negative pressure to the sealed space surrounded by the cap 70 and the head element 41 in a state in which one of the cap 70 and the head element 41 passes through the platen 3 and meets the other. In this operation, the ink is forcibly sucked from the ejection surface 40. In the positive pressure purge, ink is forcibly supplied to each head element 41 so that the ink flow path of each head element 41 becomes positive pressure by a pump (not shown) disposed between the tank 14 and the head 4. In this way, the ink is forcibly discharged from the ejection surface 40. The purge operation, the flushing operation, and the wiping operation of the ejection surface 40 of the head element 41 by the wiper 9 are referred to as the maintenance operation of the head 4.
The cap 70 is connected to a waste ink collection tank (not shown) via a tube, and the ink received by the cap 70 by the idle ejection operation is collected in the waste ink collection tank.
Further, as shown in FIG. 12, the control unit 8 described above controls the ink ejection operation of the head 4, performs the paper transport operation by the transport unit 5 and the paper feed unit 6, the lift operation of the head 4, and the lift operation of the cap 70. The motor M used in the operation of the wiper 9, the rotation operation of the rotating body 2 described later, and the pump used in the purge operation described later are controlled.

(First embodiment)
On the head housing 44, two rotary bodies 2 that respectively hold the paper P are provided between the side of each head element 41 or between adjacent head elements 41. The head casing 44 is provided with six sets of two rotating bodies 2. In each set, the two rotating bodies 2 are provided apart from each other along the central axis 20 extending in the second direction, and rotate around the central axis 20. In each set, two rotating bodies 2 are provided, but three or more rotating bodies 2 may be provided. Moreover, although two sets of the two rotary bodies 2 are provided, 1-5, the group of 7 or more may be provided. Further, the rotating body 2 is provided on the side of the head element 41 or between the adjacent head elements 41, but is not limited thereto, and may be provided in the vicinity of the head element 41. Specifically, the rotating body 2 is provided on the side of each head element 41 in the second direction, but may be arranged on both sides so as to sandwich the head 4 in the second direction. Further, it may be provided on the side of the head element 41 in the first direction.
As shown in FIGS. 2A and 2B, the lower plate 42 is provided with openings 43 so as to face both the rotating bodies 2, and each rotating body 2 is opened 43 by rotating around the central axis 20. Infested from.
The central shaft 20 is supported on the side surface of the head element 41, and the rotating body 2 rotates in a plane orthogonal to the second direction.

FIG. 3 is a perspective view of both rotating bodies 2. Each rotating body 2 includes a contact portion 21 that is formed in a semicircular shape and contacts the paper P, and a non-contact portion 22 that is a notch and does not contact the paper P along the circumferential direction. A motor M is connected to the center shaft 20, and the rotating body 2 is rotated by the motor M. The motor M is connected to the control unit 8, and the rotation operation is controlled by the control unit 8. Further, the position of the one rotating body 2 in the projecting state is accurately determined by detecting the rotational position of the one rotating body 2 in the projecting state by the sensor SE2. The rotating body 2 may be a spur having a tooth surface formed on the contact portion 21 so that the ink does not easily adhere to the contact portion 21 even if the paper P to which the ink is attached contacts the contact portion 21. .
The two rotating bodies 2 are different from each other in the rotational position of the contact portion 21, that is, the phase angle. In FIG. 3, it is assumed that they are shifted from each other by 180 °. The two rotating bodies 2 are attached to the central shaft 20 so as to rotate integrally. Therefore, when the abutting portion 21 of one rotating body 2 protrudes from the opening 43 and is in contact with the paper P, the abutting portion 21 of the other rotating body 2 is retracted into the opening 43 and the non-contacting portion. 22 faces the paper P. A state in which the contact portion 21 of each rotating body 2 protrudes from the opening 43 and the ejection surface 40 to hold the paper P is in a protruding state (the state of the left rotating body 2 of the two rotating bodies 2 in FIG. 2B). ), The contact portion 21 of each rotating body 2 retracts into the opening 43 and the discharge surface 40, and the state where it does not protrude from the opening 43 is the retracted state (the right side of the two rotating bodies 2 in FIG. 2B). The state of the rotating body 2). As described above, when the wiper 9 wipes the ejection surface 40 and the rotating body 2 is in the protruding state, the upper end portion of the wiper 9 contacts the peripheral edge of the rotating body 2 and stains the rotating body 2 with ink. End up. Since the rotator 2 is in contact with the conveyed paper P, if the ink adheres to the rotator 2, the paper P becomes dirty. Accordingly, when the wiper 9 is wiped, the rotating body 2 is switched between the protruding state and the retracted state so that the wiper 9 and the contact portion 21 of the rotating body 2 do not contact each other. Specifically, when the rotating body 2 and the wiper 9 face each other, the rotating body 2 is set in the retracted state.

FIG. 4 is a side view of the rotating body 2 of FIG. 3 viewed from the axial direction. The contact portions 21 of the two rotators 2 are continuous in the circumferential direction when viewed from the side. As a result, when the rotator 2 rotates, any one of the contact portions 21 is in a protruding state and presses the sheet P. ing. Since any one of the contact portions 21 presses the paper P, the paper P is separated from the ejection surface 40, so that the paper P can be effectively prevented from being warped and coming into contact with the ejection surface 40.
FIG. 5 is a front view of the head element 41 in the present embodiment. Two rotating bodies 2 are attached to the central shaft 20 along the axial direction, and a detection plate 230 is integrally attached to one end of the central shaft 20. A sensor SE <b> 2 is provided on the lower plate 42 so as to face the detection plate 230. A detection signal generated by the sensor SE2 is transmitted to the control unit 8. A one-way clutch 300 connected to the motor M is fitted to the central shaft 20. As shown in FIG. 6, one notch 220 is provided in the peripheral portion of the detection plate 230, and if the sensor SE <b> 2 detects the notch 220 when the detection plate 230 rotates along with the rotation of the central shaft 20. It is detected that one of the two rotating bodies 2 is in a protruding state. The one-way clutch 300 and the motor M constitute the “rotating mechanism” of the present invention.

The one-way clutch 300 is a mechanism that transmits the rotation of the motor M to the central shaft 20 in one rotation direction, but does not transmit the rotation to the motor M even if the central shaft 20 rotates in the opposite direction. Various configurations of the one-way clutch 300 are conceivable, and an example is shown in FIG. This is configured by concentrically providing the outer ring 310 and the inner shaft 320, and the central shaft 20 is fixed concentrically at the center of the inner shaft 320. The outer ring 310 is hollow and forms a slope 340 on the inner surface. A recess 350 is provided in the circumferential surface of the inner shaft 320 along the circumferential direction, and a cylindrical roller 330 is provided in the recess 350 so as to be rotatable about the center C as a rotation center. The depth of the recess 350 is different between the right end and the left end in FIG. The depth of the right end in FIG. 7 of the recess 350 is formed to be shallower than the diameter of the roller 330. The depth of the left end in FIG. 7 of the recess 350 is formed deeper than the diameter of the roller 330. The roller 330 is pressed against one side wall (right side) of the recess 350 by the elastic member 360, and the backlash in the recess 350 is suppressed. The elastic member 360 is not fixed to the roller 330 and does not hinder rotation about the center C of the roller 330 as the rotation center. The outer ring 310 has a tooth surface 370 formed on a peripheral surface thereof, and the tooth surface 370 meshes with the motor M. That is, in the one-way clutch 300, the outer ring 310 is rotated by the motor M.
A protrusion 380 that contacts the peripheral surface of the inner shaft 320 is provided from the inner surface of the outer ring 310, and the outer ring 310 and the inner shaft 320 rotate concentrically. The protrusion 380 is provided at a position different from the inclined portion 340 with respect to the axial direction of the central shaft 20.

FIGS. 8A, 8 </ b> B, and 8 </ b> C are diagrams illustrating the rotation operation of the one-way clutch 300. As shown in FIG. 8A, when the outer ring 310 is rotated counterclockwise by the motor M, the inclined portion 340 of the outer ring 310 and the roller 330 come into contact with each other. Even if the outer ring 310 further rotates and the inclined portion 340 pushes the roller 330, the roller 330 is biased by the elastic member 360, so that the position of the right end of the recess 350 is maintained. That is, the roller 330 is sandwiched between the slope portion 340 of the outer ring 310 and the bottom surface of the recess 350. The rotation around the center C of the roller 330 is restricted, and thereby the outer ring 310 and the inner shaft 320 rotate together via the roller 330. This rotation direction is the rotation direction when the rotating body 2 is rotated from the protruding state to the retracted state by the rotation of the motor M. In order to return the rotating body 2 from the retracted state to the protruding state, the outer ring 310 may be further rotated counterclockwise by the motor M.
The amount of rotation by which the control unit 8 rotates the motor M is determined by counting the number of pulses emitted from the motor M or measuring the time during which the motor M is energized. If the sensor SE2 detects the notch 220 of the detection plate 230, it is detected that one of the two rotating bodies 2 has reached the protruding state. Whether or not the one rotating body 2 has reached the retracted state is determined by counting the number of pulses emitted from the motor M after the sensor SE2 detects the notch 220 of the detection plate 230, or It is determined by measuring the energization time. In addition, the fact that one of the rotating bodies 2 has reached the protruding state can be read as the other rotating body 2 has reached the retracted state. Further, the fact that the one rotating body 2 has reached the retracted state can be read as the other rotating body 2 has reached the protruding state. If the sensor SE <b> 2 can detect, a hole or a reflecting plate may be provided in the detection plate 230 instead of the notch 220.
In this embodiment, since the protruding state of the rotating body 2 is detected by the sensor SE2, the position of the rotating body 2 in the protruding state can be accurately determined.

During the follower operation of the rotating body 2 When the ink is ejected onto the paper P, the two rotating bodies 2 are rotated following the transport operation of the paper P. By the rotation of the two rotating bodies 2, a force is applied to the central shaft 20 and the inner shaft 320 to rotate in the opposite direction, that is, clockwise.
At this time, since the motor M does not rotate, the outer ring 310 remains stationary. As shown in FIG. 8B, the outer ring 310 does not rotate, and only the inner shaft 320 is given a clockwise rotational force. The roller 330 in contact with the inclined surface portion 340 of the outer ring 310 is rotated about the center C in the counterclockwise direction by the rotational force of the inner shaft 320 in the clockwise direction, and allows the inner shaft 320 to rotate in the clockwise direction. Further, as shown in FIG. 8C, the roller 330 is pushed by the inclined portion 340 of the outer ring 310 as the inner shaft 320 rotates in the clockwise direction, and the dent 350 is directed toward the left end of the dent 350. Move in. When the elastic member 360 is compressed and the roller 330 approaches the left end of the recess 350, the depth of the recess 350 is larger than the diameter of the roller 330, so that the inclined portion 340 of the outer ring 310 can get over the roller 330. That is, the inner shaft 320 can rotate clockwise. By the clockwise rotation of the inner shaft 320, the contact portions 21 of the two rotating bodies 2 can alternately hold the paper P. Since the contact portions 21 of the two rotating bodies 2 are continuous in the circumferential direction in a side view, the sheet P can be always pressed by the contact portions 21 of any of the rotating bodies 2. Further, since the two rotating bodies 2 are rotated following the paper P, the conveyance operation of the paper P is not disturbed. Therefore, the ejection surface 40 of the head element 41 is prevented from being damaged by the warp of the paper P. The rotating body 2 is configured to rotate following the transported paper P. However, the present invention is not limited to this, and the control unit 8 causes the motor M to synchronize the transport speed of the paper P and the rotational speed of the central shaft 20. You may control the drive of.

FIGS. 9A and 9B are front views showing the wiping operation of the discharge surface 40 by the wiper 9. For convenience of illustration, the platen 3, the one-way clutch 300, the detection plate 230, and the sensor SE2 are not shown. As described above, the wiper 9 moves along the second direction to wipe the discharge surface 40, but the control unit 8 rotates the motor M at that time to switch between the protruding state and the retracted state of the rotating body 2. . Here, when the wiper 9 passes through the discharge surface 40 after wiping the discharge surface 40 and approaches the rotating body 2, if the rotating body 2 is in a protruding state, the ink wiped by the wiper 9 on the rotating body 2 is removed. Adhere to. In order to prevent this, the control unit 8 rotates the motor M as described below. The position indicated by the solid line in FIG. 9 (a) where the wiper 9 is not opposed to both rotating bodies 2, that is, the wiper 9 is positioned laterally with respect to both rotating bodies 2, is the first position, and the wiper 9 is any rotating body. A position opposed to 2, that is, a position indicated by a dotted line in FIG.
When the wiper 9 moves from the first position to the second position, the control unit 8 controls the rotation of the motor M so that the upper end portion of the wiper 9, that is, the portion where the wiper 9 wipes the discharge surface 40 is the rotating body 2. The central shaft 20 is rotated so as to face the non-contact portion 22. When the wiper 9 passes through one rotating body 2 (the right rotating body 2 in FIG. 9A) and goes to the other rotating body 2 (the left rotating body 2 in FIG. 9A), the wiper 9 The controller 8 controls the rotation of the motor M so that the non-contact portion 22 of the other rotating body 2 faces the upper end portion of the wiper 9. Specifically, the control unit 8 uses the sensor SE2 to accurately determine the position of the rotating body 2 in the protruding state, then moves the wipe 9 and before the wipe 9 reaches each rotating body 2, the motor M The central shaft 20 is rotated to set each rotating body 2 in the retracted state. That is, before the wipe 9 reaches one rotating body 2 (before the wiper 9 reaches the position indicated by the dotted line in FIG. 9A), the central axis 20 is rotated by the motor M so that the one rotating body 2 is moved. The evacuation state (the state shown in FIG. 9A) is set. In that state, the wipe 9 passes through the one rotating body. After the wipe 9 passes through the one rotating body, the motor M causes the central shaft 20 to move before the wipe 9 reaches the other rotating body 2 (before the wipe reaches the position indicated by the solid line in FIG. 9B). The other rotating body 2 is set in the retracted state (the state shown in FIG. 9B) by rotating. In this state, the wipe 9 passes through the other rotating body (the wiper moves to a position indicated by a dotted line in FIG. 9B). Thereby, the possibility that the ink wiped by the wiper 9 adheres to the rotating body 2 is reduced.

FIG. 10 is a bottom view of FIG. 9A, that is, a view of the rotating body 2 shown in FIG. 9A viewed from the A2 direction. As described above, the rotating body 2 appears and disappears from the opening 43 of the head housing 44. In the first position, the wiper 9 is bent and deformed with its upper end contacting the discharge surface 40. As described above, the wiper 9 extends along the first direction, but the width L2 in the first direction of the side edge facing the rotating body 2 at the peripheral edge of the opening 43 is the width of the wiper 9 in the first direction. It is shorter than L1. The reason is shown below.
When the wiper 9 is fitted into the opening 43 when moving from the first position toward the second position, the upper end portion that wipes the ejection surface 40 is elastically restored, and as a result, the wiped ink is scattered and the rotating body 2 is scattered. There is a possibility to adhere to. Therefore, the width L2 of the portion of the opening 43 facing the rotating body 2 is formed to be shorter than the width L1 of the wiper 9, and the wiper 9 fits in the opening 43 until the wiper 9 passes through the rotating body 2. It prevents that. Thereby, even if the wiper 9 reaches a position facing the opening 43, the elastic return of the wiper 9 can be suppressed. As a result, it is possible to suppress ink from scattering and adhering to the rotating body 2.

At the time of the flushing operation , the two adjacent head elements 41 shown in FIG. 2B alternately eject the ink. FIGS. 11A and 11B are front views showing the flushing operation. For convenience of illustration, the platen 3, the one-way clutch 300, the detection plate 230, and the sensor SE2 are not shown. As described above, since the two rotating bodies 2 are out of phase with each other, the two rotating bodies 2 cannot be set to the retracted state at the same time. Accordingly, during the flushing operation, the control unit 8 controls the rotation operation of the rotating body 2 as described below.

In FIG. 11A, when the right head element 41 performs the flushing operation, the left adjacent head element 41 does not perform the flushing operation. The control unit 8 controls the motor M so that the rotating body 2 close to the right head element 41 performing the flushing operation is in a retracted state. The rotating body 2 close to the left head element 41 is in a protruding state.
Conversely, when the left head element 41 performs the flushing operation in FIG. 11B, the right adjacent head element 41 does not perform the flushing operation. The control unit 8 controls the motor M so that the rotating body 2 close to the left head element 41 performing the flushing operation is in a retracted state. The rotating body 2 close to the right head element 41 is in a protruding state. When the head element 41 performs a flushing operation, ink may be scattered around the periphery. By setting the rotator 2 close to the head element 41 where the flushing operation is performed to the retracted state, the possibility that ink during the flushing operation adheres to the rotator 2 is reduced. Similar operation control may be performed not only during the flushing operation but also during the purge operation.

In the ink jet recording apparatus 1 according to the present embodiment, the rotating body 2 presses the paper P when the contact portion 21 is in the protruding state. When wiping the discharge surface 40 with the wiper 9, the control unit 8 controls the motor M that is a rotation mechanism so that the contact portion 21 of the rotating body 2 does not protrude from the discharge surface 40. That is, the rotating body 2 can be switched between a state in which the contact portion 21 protrudes from the discharge surface 40 and a retracted state in which the contact portion 21 does not protrude from the discharge surface 40 by rotation about the central axis 20. That is, since the central axis 20 does not move, the space corresponding to the movement stroke of the rotating body 2 accompanying the movement of the central axis 20 can be reduced in size. That is, it is possible to suppress an increase in the size of the inkjet recording apparatus 1 in the vertical direction.
Further, in the configuration in which the rotating body 2 and the central shaft 20 always rotate integrally, it is necessary to synchronize the conveyance speed of the paper P and the rotational speed of the central shaft 20, and the control for rotationally driving the central shaft 20 is compared. Complicated. Therefore, during the transport operation of the paper P, the rotating body 2 is allowed to rotate following the transport operation of the paper P, so that the control for rotationally driving the central shaft 20 is simplified.

(Second embodiment)
In the present embodiment, as shown in FIG. 13, one rotating body 2 that holds the paper P is provided on the side of each head element 41 or between adjacent head elements 41. The head casing 44 is provided with six sets of one rotating body 2. In each group, two or more rotating bodies 2 may be provided. In this case, the rotational positions of the contact portions 21 of the two or more rotating bodies, that is, the phase angles are provided to be substantially the same. . Moreover, 1-5, the group of the rotary body 2 may be provided 7 or more.
FIG. 14A is a side view of the rotating body 2 in the protruding state in the present embodiment. Each rotating body 2 has a circular hole 23 at the center, and one convex portion 24 protrudes inward from the peripheral edge of the circular hole 23. The convex portions 24 of the two rotating bodies 2 overlap each other in a side view. In the present embodiment, the central shaft 20 is formed in a semicircular cross section with a notch 25 formed in part, and a play space 26 is formed between the central shaft 20 and the circular hole 23. . The straight edge portion of the notch 25 of the central shaft 20 is in contact with the convex portion 24, and the edge portion constitutes an engaging portion 27 that engages with the convex portion 24. The convex portion 24, the engaging portion 27, and the motor M constitute the “rotating mechanism” of the present invention. Note that a one-way clutch may be employed as in the first embodiment.

  14A, 14B, and 15 are side views showing the operation of each rotating body 2. FIG. 14A shows a protruding state, FIG. 14B shows a state where the rotating body 2 is driven by the paper P being conveyed, and FIG. 15 shows a retracted state. In the protruding state, the rotating body 2 has the convex portion 24 in contact with the engaging portion 27, and the contacting portion 21 protrudes downward from the opening 43 toward the conveyance path of the paper P.

As shown in FIG. 14B, when the rotating body 2 is driven, when the sheet P is transported, the contact portion 21 of the rotating body 2 comes into contact with the sheet P, and the rotating body 2 performs the transporting operation of the sheet P. Follow and rotate clockwise. The convex portion 24 moves away from the engaging portion 27 and rotates in the play space 26. At this time, the central shaft 20 does not rotate. The rotating body 2 does not interfere with the conveyance operation of the paper P while the contact portion 21 presses the paper P. The ejection surface 40 of the head element 41 is prevented from being damaged by the warp of the paper P.

  Here, a small roller 200 that rotates in contact with the paper P may be provided on the contact portion 21 of the rotating body 2 on the upstream side in the rotation direction, that is, on the rear end side. The reason is shown. In the state shown in FIG. 14 (b), the rotating body 2 can no longer rotate in the clockwise direction, and therefore remains in this state. In this state, the rear end portion on the abutting portion 21 of the rotating body 2 continues to abut on the paper P, so that the conveyance load of the paper P is caused. Further, there is a risk of damaging the surface of the paper P. Therefore, the small roller 200 is provided at the rear end portion on the contact portion 21 of the rotating body 2, and the small roller 200 is driven to rotate with respect to the paper P to reduce the transport load of the paper P. Further, the possibility of damaging the paper P is also prevented.

When the sheet P passes through the rotating body 2 during the retraction operation of the rotating body 2, the rotating body 2 returns to the protruding state shown in FIG. The convex part 24 comes into contact with the engaging part 27 again.
As described above, when the wiper 9 wipes the discharge surface 40, the control unit 8 rotates the motor M to rotate the central shaft 20 counterclockwise. The engaging portion 27 of the central shaft 20 pushes the convex portion 24 to rotate the rotating body 2 integrally with the central shaft 20 in the counterclockwise direction. As shown in FIG. 15, the rotating body 2 reaches a retracted state in which the contact portion 21 is retracted into the opening 43. In this state, the wiper 9 wipes the ejection surface 40. The amount of rotation by which the control unit 8 rotates the motor M is determined by counting the number of pulses emitted from the motor M or measuring the time during which the motor M is energized.
When the wiper 9 wipes the discharge surface 40, the central shaft 20 is rotated counterclockwise from the protruding state shown in FIG. 14A, and the contact portion 21 is set in the retracted state. In addition, what is necessary is just to set all the rotary bodies 2 to a retracted state before the wiping operation | movement by the wiper 9. FIG.
At the time of flushing, the control unit 8 sets the rotating body 2 in the retracted state by rotating the central shaft 20 by the motor M before the ink is ejected from the head element 41. Thereby, the rotary body 2 can be accurately set to the retracted state. Note that the control unit 8 may perform control so that all the head elements 41 perform idle ejection simultaneously. In this case, all the rotating bodies 2 are set in the retracted state before the idle discharge is performed.

In the ink jet recording apparatus 1 according to the present embodiment, the rotating body 2 presses the paper P when the contact portion 21 is in the protruding state. When wiping the discharge surface 40 with the wiper 9, the control unit 8 controls the motor M that is a rotation mechanism so that the contact portion 21 of the rotating body 2 does not protrude from the discharge surface 40. That is, the rotating body 2 can be switched between a state in which the contact portion 21 protrudes from the discharge surface 40 and a retracted state in which the contact portion 21 does not protrude from the discharge surface 40 by rotation about the central axis 20. That is, since the central axis 20 does not move, the space corresponding to the movement stroke of the rotating body 2 accompanying the movement of the central axis 20 can be reduced in size. That is, it is possible to suppress an increase in the size of the inkjet recording apparatus 1 in the vertical direction.
Further, in the configuration in which the rotating body 2 and the central shaft 20 always rotate integrally, it is necessary to synchronize the conveyance speed of the paper P and the rotational speed of the central shaft 20, and the control for rotationally driving the central shaft 20 is compared. Complicated. Therefore, during the transport operation of the paper P, the rotation body 2 is made to be able to rotate following the transport operation of the paper P, and the control for rotationally driving the central shaft 20 is simplified.
Further, since the play space 26 is formed between the convex portion 24 and the engaging portion 27, the rotating body 2 can be driven and rotated while suppressing the conveyance load of the paper P when the paper P is conveyed. Further, the rotating body 2 can be rotated by the convex portion 24 and the engaging portion 27 as the central shaft 20 is driven to rotate.
In addition, since each set includes one rotator 2, the control for setting the rotator 2 to the retracted state during the idle discharge and the wiping operation is simplified. That is, since all the rotating bodies 2 need only be in the retracted state before the idle ejection and wiping operations, the control of the rotating bodies 2 is simplified.

  FIG. 16 is a view showing a modified example of the rotating body 2. In the configuration shown in FIG. 16, the rotating body 2 has a fan-shaped hole 210, and projects a rod-shaped convex portion 24 from the central axis 20 toward the fan-shaped hole 210. The side edge of the fan-shaped hole 210 with which the convex part 24 comes into contact becomes the engaging part 27, and the inside of the fan-shaped hole 210 in which the convex part 24 can rotate becomes the play space 26. That is, the convex portion 24 is provided not on the rotating body 2 but on the central axis 20. Further, a small roller 200 that rotates in contact with the paper P on the rear end side in the rotation direction on the contact portion 21 of the rotating body 2 may be provided.

In the above description, the wiper 9 extends along the first direction and is movable along the second direction. However, instead of this, the wiper 9 may extend along the second direction and be movable along the first direction.
In the above description, the two rotating bodies 2 are alternately projected during the flushing operation. However, when there is one rotating body 2 or when a plurality of rotating bodies 2 can rotate independently with respect to the central axis 20, all the rotating bodies 2 may be in a retracted state during the flushing operation.
Further, the one-way clutch mechanism 300 shown in FIG. 7 is applicable to various application examples such as a configuration in which a torsion spring is inserted between the outer ring 310 and the inner shaft 320.

  The present invention is useful when applied to a liquid ejecting apparatus such as an ink jet recording apparatus that ejects liquid onto a recording medium.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Rotating body 4 Head 8 Control part 9 Wiper 20 Central axis 21 Contact part 22 Non-contact part 40 Discharge surface 41 Head element 44 Head housing

Claims (10)

A head housing including a head element having a discharge surface for discharging liquid;
A transport mechanism for transporting a recording medium toward the head housing;
A contact portion and a non-contact portion with the recording medium are formed along a circumferential direction, the contact portion protrudes from and emerges from the discharge surface around a central axis, and the non-contact portion is the discharge surface. One or more rotating bodies that are rotatably provided so as not to protrude from the recording medium and hold the recording medium by the corresponding contact portions;
A rotating mechanism for rotating the rotating body around the central axis so as to take a protruding state in which the contact portion protrudes from the discharge surface and a retracted state in which the contact portion does not protrude from the discharge surface;
A wiper that moves along the discharge surface to wipe the discharge surface;
A controller that controls the rotating mechanism so that the rotating body takes the retracted state when the wiper passes through a portion corresponding to the rotating body of the discharging surface when the wiper wipes the discharging surface; A liquid discharge apparatus.   The liquid ejecting apparatus according to claim 1, wherein the rotating mechanism is configured such that the rotating body rotates following the recording medium conveyance operation during a recording medium conveyance operation. 3. A small roller which is provided at a peripheral portion of the contact portion of the rotating body and is rotatably provided on the upstream side in the rotation direction of the rotating body and rotates in contact with the recording medium to be conveyed. The liquid discharge apparatus according to 1. The control unit controls the head element to perform an empty ejection operation of a liquid that does not form an image on a recording medium from an ejection surface of the head element;
4. The liquid ejection device according to claim 1, wherein the controller drives the rotation mechanism so that the contact portion is in the retracted state during an empty liquid ejection operation. 5. Two or more rotators spaced apart from each other along a direction orthogonal to the conveyance direction of the recording medium are provided on the central axis so as to rotate integrally, and the abutting portions of the two or more rotators are provided on the central axis. The liquid ejecting apparatus according to claim 1, wherein the positions of the contact portions of the at least two rotating bodies are shifted from each other along the rotation direction of the rotating bodies so as to be continuous in the circumferential direction. The wiper is provided movably along the discharge surface between a first position that does not face the two or more rotating bodies and a second position that faces any of the rotating bodies,
The control unit is configured so that when the wiper moves from the first position to the second position, a portion for wiping the discharge surface of the wiper faces a non-contact portion of each of the two or more rotating bodies. The liquid ejection device according to claim 5, wherein the liquid ejection device drives a rotation mechanism. The head housing includes a plurality of head elements,
The two or more rotating bodies are disposed between two adjacent head elements,
The control unit controls the plurality of head elements so as to perform an idle ejection operation of liquid that does not form an image on a recording medium from each ejection surface of the two adjacent head elements.
The control unit sets the rotating body close to the one of the two or more rotating bodies to a retracted state when the idle discharging operation is performed from one of the discharging surfaces of the two adjacent head elements. When the idle discharge operation is performed from the other discharge surface of the two adjacent head elements, the rotary body close to the other discharge surface of the two or more rotary bodies is in a retracted state. The liquid ejection apparatus according to claim 5 or 6, wherein the liquid ejection apparatus controls a rotation mechanism. The head housing has a plurality of the head elements,
The plurality of head elements are arranged along a conveyance direction in which a recording medium is conveyed, and the rotating body is provided between the plurality of head elements. The liquid discharge apparatus as described. The rotating mechanism includes a protrusion provided on one of said rotary member and said central axis, provided on the other of said rotating body and said central axis, and an engaging portion engaged with the convex portion And
The liquid ejection device according to claim 1, wherein a play space is formed between the convex portion and the engaging portion in the circumferential direction. The head housing is provided with an opening through which the contact portion passes when it appears and disappears.
The wiper is formed of an elastic material extending in one direction, and is provided to be movable along a discharge surface between a first position that does not face the rotating body and a second position that faces the rotating body. In the first position, the portion for wiping the discharge surface of the wiper is elastically deformed in contact with the discharge surface,
10. The liquid ejection apparatus according to claim 1, wherein a width of the portion of the opening facing the rotating body in the one direction is shorter than a width of the wiper in the one direction.

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