JP2009126680A - Recording medium transport device - Google Patents

Abstract

To suppress double feeding of recording media.
A sheet transport device 10 separates only one sheet from a sheet storage unit 11 and a plurality of sheets P sent out from the sheet storage unit 11, and transports the separated sheet P while sandwiching the separated sheet P. A friction member 21 disposed below the paper P sent from the paper storage unit 11 to the separation roller pair 13, a friction member moving mechanism 22 for moving the friction member 21 in the vertical direction, and the separation roller pair 13. A conveyance roller pair 16 that conveys the conveyed paper P is provided. The sheet conveying device 10 has a friction member moving mechanism 22 that moves the friction member 21 to a contact position where the separation roller pair 13 comes into contact with the sheet P that has been multi-fed when the pair of separation rollers 13 is released. It further has a control unit 60 for controlling.
[Selection] Figure 1

Description

  The present invention relates to a recording medium conveying apparatus that conveys a recording medium.

  Patent Document 1 includes a table on which a plurality of forms can be placed, a form extruding roller that sends out forms from the stage, a form pulling roller that conveys a form sent out by the form extruding roller, and a form pulling roller. Among the multiple forms sent out from the platform while sandwiching the forms between them, the two-sheet feed prevention roller that returns the lower form to the platform side and the form conveyed by the form pulling roller facing each other are sandwiched There is described a form delivery mechanism having a feed roller and a tension roller that are conveyed while having a detector that detects the leading edge of the form conveyed by the feed roller and the tension roller. In this form delivery mechanism, when a form is detected by the detector, the form push-out roller and the two-sheet feed prevention roller move away from the form. As a result, the form feeding load by the feeding roller and the tension roller is reduced, and the form feeding with less speed fluctuation can be realized.

JP 59-108631 A

  However, in the form feeding mechanism described in Patent Document 1, the form pushing roller and the two-sheet feed preventing roller are moved away from the form in order to reduce the load of form feeding by the feeding roller and the tension roller. However, when the separated form is in contact with another form that comes into contact with the form at the time of separation, for example, the electrostatic force, the adhesive force of the medium, and the edge of the medium A form to be transported by a binding force such as a hooking force and another form are double-fed.

  Accordingly, an object of the present invention is to provide a recording medium transport device that suppresses double feeding of recording media.

  The recording medium transport device of the present invention includes a recording medium storage unit that can store a plurality of stacked recording media, and a plurality of recording media that are sent in an overlapping manner from the recording medium storage unit by rotating in the same direction. A separation roller pair that separates one sheet and rotates in opposite directions while sandwiching the separated recording medium, and conveys the recording medium conveyed by the separation roller pair. And a friction member disposed below the recording medium fed from the recording medium storage unit to the separation roller pair between the recording medium storage unit and the separation roller pair, and the friction member Between the contact position where it comes into contact with another recording medium which is double-fed together with the recording medium transported by the transport section and the separation position where it does not contact with the other recording medium. A friction member moving mechanism that moves the friction member, and a control that controls the friction member moving mechanism so that the friction member is moved to the contact position after the pair of separation rollers is released from the holding of the recording medium. Means.

  According to this, even when the holding of the recording medium by the pair of separation rollers is released, the other recording medium that has been multi-fed and the friction member come into contact with each other. It becomes difficult to send. Therefore, it is possible to transport only one recording medium separated by the separation roller pair.

  In the present invention, it is preferable that a static frictional force of the friction member with respect to the another recording medium is smaller than a conveying force of the recording medium by the conveying unit and larger than a coupling force between the recording media that are double-fed. Thus, another recording medium can be separated from the recording medium without hindering the conveyance of the recording medium by the conveying unit.

  In the present invention, it is preferable that the friction member is in contact with a central region in the width direction perpendicular to the transport direction of the other recording medium at the contact position. As a result, the friction member comes into contact with the central region in the width direction of another recording medium at the contact position, so that the other recording medium is difficult to skew. As a result, the recording medium conveyed by the conveying unit is also difficult to skew.

  At this time, the friction member may be in contact with the entire width direction of the other recording medium at the contact position. As a result, the recording medium conveyed by the conveying unit is more difficult to skew.

  In another aspect, the recording medium transporting apparatus of the present invention overlaps with the recording medium storage unit that can store a plurality of stacked recording media, and overlaps the recording medium storage unit by rotating in the same direction. A separation roller pair that separates only one sheet from the plurality of recorded recording media and that conveys the separated recording medium in the conveying direction by rotating the recording medium in opposite directions while sandwiching the separated recording medium, and the separation roller pair Between the transport unit that transports the transported recording medium and the recording medium storage unit and the separation roller pair, the recording medium is disposed above the recording medium fed from the recording medium storage unit to the separation roller pair. One of the pressure roller and another recording medium in which the pressure member is transported together with the recording medium via the recording medium conveyed by the conveying unit constitutes the separation roller pair. After the press contact member moving mechanism for moving the press contact member between the press contact position that presses against the separation roller and the separation position that does not contact the recording medium, and after the nipping of the recording medium by the pair of separation rollers is performed, Control means for controlling the pressure member moving mechanism so as to move the pressure member to the pressure position.

  According to this, even when the holding of the recording medium by the pair of separation rollers is released, another recording medium that has been multi-fed is pressed against one of the separation rollers, so that the recording medium is conveyed by the conveying unit. It becomes difficult to double feed. Therefore, it is possible to transport only one recording medium separated by the separation roller pair.

  In the present invention, the pressing force of the pressing member against the other recording medium is such that the static frictional force between the one separation roller and the other recording medium is smaller than the conveying force of the recording medium by the conveying unit. In addition, it is preferable that the size is larger than the coupling force between the recording media that are double-fed. Thus, another recording medium can be separated from the recording medium without hindering the conveyance of the recording medium by the conveying unit.

  In the present invention, the separation roller pair is disposed at a position where the pair of separation rollers can come into contact with a central region in the width direction perpendicular to the conveyance direction of the recording medium, and the pressing member is located at the pressing position of the recording medium. It is preferable to press-contact the central region. As a result, the central area of another recording medium is pressed against one of the separation rollers, so that it is difficult for another recording medium to skew. As a result, the recording medium conveyed by the conveying unit is also difficult to skew.

  In the present invention, the one separation roller constituting the separation roller pair is a retard roller disposed below the recording medium fed from the recording medium storage unit, and the other constituting the separation roller pair The separation roller is a feed roller disposed above the recording medium fed from the recording medium storage unit, and when the nipping of the recording medium by the pair of separation rollers is performed, the feed roller is It is preferable that the retard roller does not move. As a result, even when the nipping of the recording medium by the separation roller pair is performed, the retard roller is present at the same position, so that the amount of movement of the pressure contact member can be reduced.

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

  FIG. 1 is a schematic side view of an ink jet printer that employs a sheet conveying apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic configuration diagram of the separation roller pair and the separation roller moving mechanism shown in FIG. FIG. 3 is a schematic configuration diagram of the friction member and the friction member moving mechanism shown in FIG. 1.

  As shown in FIG. 1, the inkjet printer 1 is a color inkjet printer having four inkjet heads 2. The ink jet printer 1 is provided with a sheet conveying device 10 on the left side in FIG. 1 and a paper discharge unit 40 on the right side in FIG. Between the paper transport device 10 and the paper discharge unit 40, a belt transport device 50 that transports the paper (recording medium) P transported from the paper transport device 10 toward the paper discharge unit 40 is provided. . In addition, the printer 1 is provided with a control unit 60 that controls the operation of the paper transport apparatus 10.

  The belt conveyance device 50 includes a pair of belt rollers 51 and 52, an endless conveyance belt 53 wound around the rollers 51 and 52, and a pressing roller 55. The outer peripheral surface of the conveyance belt 53, that is, the conveyance surface 53a is subjected to silicone treatment and has adhesiveness. The pressing roller 55 is disposed at a position above the belt roller 51 and sandwiching the conveyance belt 53 with the belt roller 51. The pressing roller 55 is urged toward the transport surface 53a and presses the paper P transported from the paper transport device 10 against the transport surface 53a.

  With this configuration, the paper P pressed against the transport surface 53a is transported in the transport direction A (the direction of arrow A in FIG. 1) while being held by the adhesive force of the transport surface 53a. At this time, the belt roller 52 on the downstream side in the transport direction receives a driving force from a driving motor (not shown) and rotates in the clockwise direction (arrow B direction) in FIG.

  A peeling member 9 is provided immediately downstream in the conveyance direction A of the belt conveyance device 50. The peeling member 9 is configured to peel the paper P held on the conveyance surface 53a from the conveyance surface 53a and send it to the right paper discharge unit 40.

  In a region surrounded by the conveyance belt 53, a substantially rectangular parallelepiped-shaped platen 56 that supports the inkjet head 2 from the inner peripheral side by contacting with the lower surface of the conveyance belt 53 on the upper side is disposed. Has been.

  The four inkjet heads 2 are arranged along the transport direction A in correspondence with four color inks (magenta, yellow, cyan, and black). That is, the ink jet printer 1 is a line printer. The inkjet head 2 has an elongated rectangular parallelepiped shape whose longitudinal direction extends in a direction perpendicular to the transport direction A (a direction perpendicular to the paper surface in FIG. 1). The inkjet head 2 has a laminate (both not shown) in which a flow path unit in which an ink flow path including a pressure chamber is formed and an actuator that applies pressure to the ink in the pressure chamber are bonded together. Ink is ejected from a number of nozzles (not shown) formed on the bottom surface.

  The bottom surface of the inkjet head 2 and the conveyance surface 53a of the conveyance belt 53 facing the inkjet head 2 are parallel to each other, and a sheet conveyance path is formed between these surfaces. With this configuration, when the paper P transported by the transport belt 53 sequentially passes immediately below the four inkjet heads 2, ink of each color is ejected from the nozzles toward the upper surface (printing surface) of the paper P. Thus, a desired color image is formed.

  As shown in FIGS. 1 to 3, the sheet transport device 10 includes a sheet storage unit 11 that can store a plurality of stacked sheets P, a pickup roller 12 that feeds the sheet P from the sheet storage unit 11, and a pickup roller 12. A separating roller pair 13 that separates and conveys only one sheet P in the conveying direction A when the sheet P sent out by the sheet P is fed with another sheet P in contact with the sheet P; Of the retard roller (one separation roller) 14 and the feed roller (the other separation roller) 15 constituting the pair 13, the separation roller moving mechanism 30 that moves the upper feed roller 15 in the vertical direction, and the separation roller pair 13. A conveyance roller pair (conveyance unit) 16 that conveys the paper P conveyed by the belt conveyance device 50 and a drive motor 7 that rotates the pickup roller 12. (See FIG. 4), drive motors 74 and 75 (see FIG. 4) that rotate the retard roller 14 and the feed roller 15 in the same direction, and the two transport rollers 17 and 18 that constitute the transport roller pair 16, And a drive motor 78 (see FIG. 4) for rotating the transport roller 18 located above.

  In addition, the sheet conveying device 10 includes a friction member 21 disposed between the sheet storage unit 11 and the separation roller pair 13 below the sheet P fed from the sheet storage unit 11 to the separation roller pair 13. And a friction member moving mechanism 22 for moving the member 21 in the vertical direction.

  A sheet sensor 61 connected to the control unit 60 is provided immediately downstream in the conveyance direction A of the conveyance roller pair 16. The sheet sensor 61 detects the front end of the sheet P conveyed by the conveying roller pair 16 and transmits a detection signal to the control unit 60.

  The pickup roller 12 feeds the sheet P to the separation roller pair 13 by rotating and contacting the uppermost sheet P among the plurality of sheets P stored in the sheet storage unit 11. The pick-up roller 12 is moved to a contact position (see FIG. 5A) that contacts the paper P when the paper P is sent out by a moving mechanism (not shown) and when the sent paper P is conveyed by the separation roller pair 13. It is moved between the paper P and a separation position (see FIG. 5B). The drive motor 72 and the moving mechanism (not shown) are controlled by the control unit 60.

  As shown in FIG. 2, the separation roller pair 13 includes a retard roller 14 and a feed roller 15 facing each other, and the retard roller 14 is rotatably supported by the printer body. The retard roller 14 and the feed roller 15 are disposed at a position where they can come into contact with the central region in the width direction (left-right direction in FIG. 2) orthogonal to the conveyance direction A of the paper P. The feed roller 15 is disposed above the sheet P sent from the sheet storage unit 11, and the retard roller 14 is disposed below the sheet P.

  The retard roller 14 is normally rotated in the same direction as the feed roller 15 by the drive motor 74. However, when the retard roller 14 is in contact only with the paper P conveyed by the feed roller 15, the outer periphery of the retard roller 14 is in contact with the shaft. It is configured to slide and rotate in the reverse direction. That is, when another paper P that has been multi-fed together with the paper P to be transported is separated from the paper P to be transported, the feed roller 15 and the retard roller 14 rotate in the same direction, and the other paper P is moved by the retard roller 14. It is sent to the paper storage unit 11 side. When only the paper P to be transported is transported while being sandwiched between both rollers 14 and 15, the retard roller 14 rotates in the opposite direction to the feed roller 15.

  As shown in FIG. 2, the separation roller moving mechanism 30 includes a support member 31 that rotatably supports the feed roller 15, and a solenoid 32 that moves the feed roller 15 in the vertical direction together with the support member 31. The support member 31 is fixed to the rod 32 a of the solenoid 32. Further, the solenoid 32 and the transport motors 74 and 75 are controlled by the control unit 60.

  In this configuration, when the retard roller 14 and the feed roller 15 are both rotated counterclockwise in FIG. 1 under the control of the control unit 60, the pickup among the plurality of sheets P fed from the pickup roller 12 is picked up. The sheet P that has come into contact with the roller 12 is mainly conveyed in the conveying direction A by the feed roller 15, and another sheet P that is double-fed under the sheet P is opposite to the conveying direction A by the retard roller 14. Only one sheet P among the plurality of sheets P transported and fed in the transport direction is transported in the transport direction A.

  Further, when the solenoid 32 is driven under the control of the control unit 60, the rod 32 a of the solenoid 32 extends as shown in FIG. 2A, and the sheet P is fed between the feed roller 15 and the retard roller 14. The feed roller 15 moves to a clamping position where clamping is possible. On the other hand, when the drive of the solenoid 32 is stopped, as shown in FIG. 2 (b), the rod 32a contracts, and the retard roller 14 and the feed roller 15 feed to the open position where the nipping of the paper P is performed. The roller 15 moves.

  The conveyance roller pair 16 is also composed of two conveyance rollers 17 and 18 facing each other, and both are rotatably supported by the printer main body. The transport roller 17 is a driven roller that rotates as the paper P is transported by the transport roller 18. The drive motor 78 is controlled by the control unit 60. In this configuration, the conveyance roller 18 rotates counterclockwise in FIG. 1 under the control of the control unit 60, so that the conveyance roller pair 16 conveys the belt while sandwiching the paper P conveyed from the separation roller pair 13. Transport to device 50.

  As shown in FIG. 3, the friction member 21 has a substantially rectangular parallelepiped shape that is long in the width direction of the paper P (left-right direction in FIG. 3) and has a length that can contact the entire width direction of the paper P. ing. Further, the friction member 21 is a friction material (for example, rubber) in which the static friction force with respect to the paper P is smaller than the transport force of the paper P by the transport roller pair 16 and larger than the coupling force between the multi-feed paper P. Or resin). That is, when the sheet P conveyed by the conveying roller pair 16 and the friction member 21 come into contact with each other, the conveying force is larger than the static frictional force, so the sheet P is conveyed by the conveying roller pair 16. When another paper P fed with P and the friction member 21 come into contact with each other, the static frictional force is larger than the coupling force between the papers, so that the transported paper P and another paper P are separated. This prevents double feeding of another sheet P.

  The friction member moving mechanism 22 includes a support member 24 that supports the friction member 21, and a solenoid 23 that moves the friction member 21 in the vertical direction together with the support member 24. The support member 24 is fixed to the rod 23 a of the solenoid 23. The solenoid 23 is controlled by the control unit 60.

  In this configuration, when the solenoid 23 is driven by the control of the control unit 60, the rod 23a of the solenoid 23 is extended and another sheet P2 fed to the friction member 21 as shown in FIG. The friction member 21 is moved to a contact position where the two contact with each other. On the other hand, when the drive of the solenoid 23 is stopped, the rod 23a contracts as shown in FIG. 3A, and the friction member 21 moves to a separation position where the friction member 21 and the paper P1, P2 are separated.

  FIG. 4 is a control system diagram of the sheet conveying apparatus 10. The control unit 60 is configured by, for example, a general-purpose personal computer. Such a computer stores hardware such as a CPU, a ROM, a RAM, and a hard disk, and various software including a program for controlling the operation of the sheet conveying device 10 is stored in the hard disk. The controller 60 controls the drive motors 72, 74, 75, 78 and the solenoids 23, 32.

  Next, a sheet conveying operation in the sheet conveying apparatus 10 will be described with reference to FIG. FIG. 5 is an explanatory diagram showing operation states of the pickup roller 12, the friction member 21, and the feed roller 15 during paper conveyance. When a conveyance start signal for conveying the paper P is transmitted from a PC (personal computer) or the like to the control unit 60, the control unit 60 is in contact with the paper P as shown in FIG. The drive motor 72 is driven so as to rotate. Thus, the paper P is sent out from the paper storage unit 11 toward the separation roller pair 13.

  Next, the control unit 60 drives the drive motors 74 and 75 and the solenoid 32 so that the sheet P1 can be rotated while being sandwiched between the feed roller 15 and the retard roller 14. At this time, even if a plurality of sheets P1 and P2 are multi-fed from the sheet storage unit 11, only the sheet P1 in contact with the feed roller 15 is conveyed in the conveyance direction A while being sandwiched by the separation roller pair 13 as described above. Is done. When the paper P1 starts to be conveyed by the separation roller pair 13, the control unit 60 moves the pickup roller 12 to the separation position and stops its rotation as shown in FIG. 5B. As described above, the drive of the drive motor 72 is stopped while controlling the moving mechanism (not shown).

  Next, the control unit 60 drives the drive motor 78 so that the transport roller 18 rotates. In this way, the paper P <b> 1 transported by the separation roller pair 13 is transported to the belt transport device 50. At this time, when the conveyance of the paper P is started by the conveyance roller pair 16, the front end of the paper P is detected by the paper sensor 61 as shown in FIG. Based on the detection signal of the paper sensor 61, the control unit 60 opens the paper P1 by the separation roller pair 13 and the retard roller 14 and the feed roller 15 as shown in FIG. The driving of the solenoid 32 and the transport motors 74 and 75 is stopped so that the rotation of the motor is stopped.

  Next, when the nipping by the separation roller pair 13 is released, the control unit 60 drives the solenoid 23 so that the friction member 21 rises from the separation position and moves to the contact position. At this time, since the friction member 21 comes into contact with another paper P2 that has been fed together with the paper P1, the paper P2 is not double fed as the paper P1 is conveyed. At this time, since the friction member 21 contacts the entire width direction of the paper P2, the paper P2 is pulled by the paper P1 to be transported and is not easily skewed. As a result, the sheet P1 transported by the transport roller pair 16 is also difficult to skew. In this way, only one sheet P can be transported to the belt transport device 50. Thereafter, ink is ejected onto the paper P1, and a desired image is formed on the paper P1.

  In addition, when the sheet P2 does not exist at a position facing the friction member 21 when the nipping by the separation roller pair 13 is performed, and the sheet P2 is later double fed along with the conveyance of the sheet P1. The paper P1 and the friction member 21 come into contact first. However, since the static frictional force of the friction member 21 with respect to the paper P is smaller than the transporting force of the paper P by the transport roller pair 16, the paper P1 is transported without being interrupted. When the paper P2 is double-fed and contacts the friction member 21, the paper P2 is not double-fed as described above.

  As described above, according to the paper transport device 10 of the present embodiment, even if the paper P1 is nipped by the separation roller pair 13, another paper P2 that has been multifed and the friction member 21 come into contact with each other. Sheet P2 is difficult to double-feed with the sheet P1 conveyed by the conveying roller pair 16. Therefore, it becomes possible to convey only one sheet P1 separated by the separation roller pair 13.

  In the present embodiment, the friction member 21 has a length that can contact the entire width direction of the paper P, but has a length that allows the friction member to contact only the central region of the paper P in the width direction. May be. Also in this case, when the friction member and the paper P come into contact with each other, it is possible to suppress the skew of the paper P that is in contact with the paper P and the paper P that is transported by the transport roller pair 16. Further, the static frictional force of the friction member 21 against the paper P may not be set only by the material constituting the friction member 21. That is, the contact position is a position where the paper P is bent upward by the contact with the friction member, and the contact force at which the friction member and the paper P are in contact with each other and the constituent material of the friction member described above. You may set so that such a static frictional force may arise.

  Subsequently, a second embodiment of the present invention will be described. FIG. 6 is a schematic side view of an ink jet printer that employs a paper conveyance device according to a second embodiment of the present invention. FIG. 7 is a schematic configuration diagram of the pressure contact member and the solenoid shown in FIG.

  The ink jet printer 201 according to the present embodiment is the same as the first embodiment except that the paper transport device 210 is slightly different from the configuration of the paper transport device 10 according to the first embodiment. Components similar to those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the present embodiment, the sheet conveying device 210 replaces the friction member 21 and the friction member moving device 22 of the first embodiment with a pressure contact member 81 and a solenoid (pressure contact member moving mechanism) 82 that moves the pressure contact member 81 in the vertical direction. Other than these, the configuration is the same as that of the first embodiment.

  As shown in FIGS. 6 and 7, the press contact member 81 has a substantially rectangular parallelepiped shape, and is sent from the paper storage unit 11 to the separation roller pair 13 between the paper storage unit 11 and the separation roller pair 13. The sheet P is disposed at a position above the sheet P and in contact with the central region in the width direction of the sheet P. The pressure contact member 81 is fixed to the rod 82 a of the solenoid 82. The solenoid 82 is controlled by the control unit 260.

  In this configuration, when the solenoid 82 is driven by the control of the control unit 260, the rod 82a of the solenoid 82 is extended and the press contact member 81 is conveyed by the conveying roller pair 16 as shown in FIG. The pressure contact member 81 moves to a pressure contact position where the paper P2 that is double-fed together with the paper P1 via the paper P1 is pressed against the retard roller 14. At this time, the pressure contact force of the pressure contact member 81 on the other sheet P2 is such that the static frictional force between the retard roller 14 and the sheet P2 is smaller than the conveyance force of the sheet P1 conveyed by the conveyance roller pair 16, and The size is set to be larger than the coupling force between the double fed sheets P1 and P2. By setting the pressure contact force in this way, when trying to press the paper P2 against the retard roller 14 via the paper P1 by the pressure contact member 81, the paper P2 is not overlapped to the vicinity of the retard roller 14. Even when the paper P1 comes into contact with the retard roller 14, the static friction force is smaller than the transport force of the paper P1 transported by the transport roller pair 16, so that the paper P1 is transported without being interrupted. Thereafter, when the sheet P2 is pressed against the retard roller 14, and when the sheet P2 is pressed against the retard roller 14 when the pressing member 81 is moved to the pressing position, the retard roller 14 and the sheet P2 are contacted. Since the static frictional force between them is larger than the coupling force between the fed papers P1 and P2, the transported paper P1 and the transported paper P2 are separated, and the transported roller pair 16 transports the paper P1. It is possible to prevent double feeding of another sheet P2 without hindering the conveyance.

  On the other hand, when the driving of the solenoid 82 is stopped by the control of the control unit 260, the rod 82a contracts as shown in FIG. 81 moves.

  Next, a sheet conveying operation in the sheet conveying apparatus 210 will be described with reference to FIG. FIG. 8 is an explanatory diagram showing operation states of the pickup roller 12, the pressure contact member 81, and the feed roller 15 during paper conveyance. When a conveyance start signal for conveying the paper P is transmitted from the PC (personal computer) or the like to the control unit 260, the control unit 260 is in contact with the paper P as shown in FIG. The drive motor 72 is driven so as to rotate. Thus, the paper P is sent out from the paper storage unit 11 toward the separation roller pair 13.

  Next, the control unit 260 drives the drive motors 74 and 75 and the solenoid 32 so as to be able to rotate while sandwiching the paper P1 between the feed roller 15 and the retard roller 14. At this time, even if a plurality of sheets P1 and P2 are multi-fed from the sheet storage unit 11, only the sheet P1 in contact with the feed roller 15 is conveyed in the conveyance direction A while being sandwiched by the separation roller pair 13 as described above. Is done. Then, when the paper P1 starts to be conveyed by the separation roller pair 13, the control unit 260 moves the pickup roller 12 to the separation position and stops its rotation as shown in FIG. 8B. As described above, the drive of the drive motor 72 is stopped while controlling the moving mechanism (not shown).

  Next, the control unit 260 drives the drive motor 78 so that the transport roller 18 rotates. In this way, the paper P <b> 1 transported by the separation roller pair 13 is transported to the belt transport device 50. At this time, when the conveyance of the paper P is started by the conveyance roller pair 16, the front end of the paper P is detected by the paper sensor 61 as shown in FIG. Based on the detection signal of the paper sensor 61, the control unit 260 opens the paper P1 by the separation roller pair 13 and the retard roller 14 and the feed roller 15 as shown in FIG. 8C. The driving of the solenoid 32 and the transport motors 74 and 75 is stopped so that the rotation of the motor is stopped.

  Next, when the nipping by the separation roller pair 13 is released, the control unit 260 drives the solenoid 82 so that the pressure contact member 81 descends from the separation position and moves to the pressure contact position. At this time, as shown in FIG. 8C, the pressure contact member 81 presses the front end of the paper P2 fed through the paper P1 transported by the transport roller pair 16 against the retard roller 14, so that the paper P2 is not double fed as the paper P1 is conveyed. At this time, the press contact member 81 presses the center area of the paper P 1, so that the paper P 1 is not skewed by the press contact of the press contact member 81. In addition, the central region of the paper P2 is pressed against the retard roller 14 via the paper P1. Therefore, even if the paper P2 is pulled by the paper P1 to be conveyed, it is difficult to skew. As a result, the sheet P1 transported by the transport roller pair 16 is also difficult to skew. In this way, only one sheet P can be transported to the belt transport device 50. Thereafter, ink is ejected onto the paper P1, and a desired image is formed on the paper P1.

  As described above, according to the sheet conveying device 210 of the present embodiment, even if the nipping of the sheet P1 by the separation roller pair 13 is released, another fed sheet P2 is pressed against the retard roller 14, so that Sheet P2 is difficult to double-feed with the sheet P1 conveyed by the conveying roller pair 16. Therefore, it becomes possible to convey only one sheet P1 separated by the separation roller pair 13. The separation roller moving mechanism 30 moves the feed roller 15 and does not move the retard roller 14 when releasing the nipping of the paper P by the separation roller pair 13. As described above, even when the nipping of the paper P by the separation roller pair 13 is performed, the retard roller 14 does not move and exists at the same position, so that the amount of movement of the pressing member 81 can be reduced. If the retard roller 14 is moved instead of the feed roller 15, it is necessary to move the pressing member 81 to a position where the paper P <b> 2 can be pressed against the retard roller 14, and the movement amount increases.

  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, the separation roller moving mechanism 30 may move the retard roller 14. Further, the paper sensor 61 may not be provided. In this case, the holding of the separation roller pair 13 with respect to the paper P may be released after a predetermined time has elapsed from when the paper P is sent out from the paper storage unit 11 by the pickup roller 12. At this time, the friction member 21 and the pressure contact member 81 may be moved. Further, after the friction member 21 and the pressure contact member 81 are released by the separation roller pair 13, that is, after a predetermined time has elapsed from when the separation roller pair 13 was released, the contact position and the pressure contact member 81 are pressed. You may move to a position. Even in this case, the same effect as described above can be obtained. The predetermined time in this case is, for example, within the time from when the paper P starts to be transported by the transport roller pair 16 to when the paper P starts to be transported by another transport device (for example, the belt transport device 50). It is desirable.

  Further, the transport roller pair 16 may be configured by a transport mechanism capable of transporting the recording medium. When the friction member 21 is in contact with only the paper P2, the static friction force of the friction member 21 with respect to the paper P2 may be larger than the conveyance force of the paper P1 conveyed by the conveyance roller pair 16. Further, the pressing member 81 may have a shape capable of pressing not only the central region in the width direction of the paper P but also the entire width direction of the paper P. In addition, the paper transport apparatuses 10 and 210 of the above-described embodiment are employed in an ink jet printer, but may be employed in any apparatus that transports a recording medium.

1 is a schematic side view of an ink jet printer in which a paper transport device according to a first embodiment of the present invention is employed. FIG. 2 is a schematic configuration diagram of a separation roller pair and a separation roller moving mechanism illustrated in FIG. 1. It is a schematic block diagram of the friction member shown in FIG. 1, and a friction member moving mechanism. FIG. 3 is a control system diagram of the sheet conveying apparatus. FIG. 6 is an explanatory diagram illustrating operation states of a pickup roller, a friction member, and a feed roller during sheet conveyance. It is a schematic side view of the inkjet printer by which the paper conveying apparatus by 2nd Embodiment of this invention was employ | adopted. It is a schematic block diagram of the press-contact member and solenoid shown in FIG. FIG. 10 is an explanatory diagram illustrating operation states of a pickup roller, a pressure contact member, and a feed roller during paper conveyance.

Explanation of symbols

10,210 Paper transport device (recording medium transport device)
11 Paper storage unit (recording medium storage unit)
13 Separation roller pair 14 Retard roller (one separation roller)
15 Feed roller (the other separation roller)
16 Transport roller pair (transport section)
DESCRIPTION OF SYMBOLS 21 Friction member 22 Friction member moving mechanism 30 Separation roller moving mechanism 60,260 Control part (control means)
81 Pressure member 82 Solenoid (Pressure member moving mechanism)

Claims (8)

A recording medium storage unit capable of storing a plurality of stacked recording media;
By rotating in the same direction, only one sheet is separated from the plurality of recording media sent out in an overlapping manner from the recording medium storage unit, and rotated in the opposite directions while sandwiching the separated recording medium. A separation roller pair that conveys in the conveying direction,
A transport unit for transporting the recording medium transported by the pair of separation rollers;
A friction member disposed below the recording medium sent from the recording medium storage unit to the separation roller pair between the recording medium storage unit and the separation roller pair;
A friction member that moves the friction member between a contact position where the friction member contacts another recording medium that is double-fed together with the recording medium transported by the transport unit and a separation position that does not contact the other recording medium. A moving mechanism;
And a control means for controlling the friction member moving mechanism so that the friction member is moved to the contact position after the separation roller pair is held open. Recording medium transport device.   2. The static frictional force of the friction member with respect to the another recording medium is smaller than the conveying force of the recording medium by the conveying unit and larger than the coupling force between the recording media that are double-fed. 2. A recording medium conveying apparatus according to 1.   3. The recording medium conveyance device according to claim 1, wherein the friction member is in contact with a central region in a width direction perpendicular to the conveyance direction of the another recording medium at the contact position.   The recording medium conveying apparatus according to claim 3, wherein the friction member is in contact with the entire width direction of the another recording medium at the contact position. A recording medium storage unit capable of storing a plurality of stacked recording media;
By rotating in the same direction, only one sheet is separated from the plurality of recording media sent out in an overlapping manner from the recording medium storage unit, and rotated in the opposite directions while sandwiching the separated recording medium. A separation roller pair that conveys in the conveying direction,
A transport unit for transporting the recording medium transported by the pair of separation rollers;
A pressure contact member disposed above the recording medium fed from the recording medium storage unit to the separation roller pair between the recording medium storage unit and the separation roller pair;
The press contact position and the recording medium in which the press contact member presses another recording medium, which is double-fed together with the recording medium via the recording medium transported by the transport unit, to one of the separation rollers constituting the separation roller pair A pressure contact member moving mechanism for moving the pressure contact member between separated positions that do not contact with
And a control means for controlling the pressing member moving mechanism so as to move the pressing member to the pressing position after the separation roller pair is held open to the recording medium. Recording medium transport device.   The pressure contact force of the pressure contact member with respect to the other recording medium is such that the static frictional force between the one separation roller and the other recording medium is smaller than the conveyance force of the recording medium by the conveyance unit, and the multi-feed is performed. 6. The recording medium conveying apparatus according to claim 5, wherein the recording medium conveying apparatus has a size larger than a coupling force between the recording media. The separation roller pair is disposed at a position where it can come into contact with a central region in the width direction perpendicular to the conveyance direction of the recording medium,
The recording medium conveying apparatus according to claim 5, wherein the press contact member presses the central region of the recording medium at the press contact position. One separation roller constituting the pair of separation rollers is a retard roller disposed below the recording medium sent out from the recording medium storage unit,
The other separation roller constituting the pair of separation rollers is a feed roller disposed above the recording medium sent out from the recording medium storage unit;
8. The apparatus according to claim 5, wherein when the nipping of the recording medium by the separation roller pair is released, the feed roller moves upward and the retard roller does not move. 9. Recording medium transport device.

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