JP2018140844A - Sheet conveying device and image forming device equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet conveying device capable of achieving, in a simple constitution, a mechanism that can provide a sheet member such as paper with a suitable stiffness in discharging and can exert no conveying load on the sheet member when the sheet member is conveyed in a direction of returning the sheet member to the inside, and an image forming device equipped with the mechanism.SOLUTION: A sheet discharge part 30 comprises a corrugation member 70 and a lever part 80. The corrugation member is swung toward a discharge direction side by a force exerted when a tip of a sheet conveyed in a discharge direction toward a sheet discharge port 37 is brought into contact and arranged in a first position capable of pressing the sheet. Also, the corrugation member is swung toward a return direction side by being brought into contact with a sheet conveyed in a return direction opposite to the discharge direction and arranged in a second position in which stiffening to a sheet passing through the corrugation member is released.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet member, and more particularly, to a sheet conveying apparatus that includes a mechanism that sits on a sheet member and discharges the sheet member from a sheet discharge port, and an image forming apparatus including the same.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a copying machine or a printer is provided with a sheet conveying device for discharging a sheet (sheet member) on which an image is formed to the outside. The sheet conveying device is provided with a pair of conveying rollers for conveying a sheet and a corrugation member that sits on and discharges the sheet on which the image is formed. The waist of the sheet indicates resistance when a bending force is applied to the sheet, and is also referred to as “stiffness” or “rigidity”. The conventional corrugation member presses the paper in the direction perpendicular to the paper discharge direction (perpendicular to the paper surface) when the paper is discharged, thereby forming a wave-like undulation in the paper in the width direction. And strengthen the paper. As a result, the discharged paper does not hang down immediately after being discharged, and it is possible to prevent the stacked state of the sheets stacked on the discharge tray or the stacking order from being disturbed.

  By the way, the conventional corrugation member presses the paper even when the paper is transported in the direction of returning from the discharge portion to the inside for duplex printing. For this reason, a load is applied to the sheet during conveyance in the return direction, preventing the sheet from being smoothly conveyed, and in some cases, the sheet may be jammed. In addition, when the wave shape formed on the sheet returns to the original state during conveyance in the return direction, an abnormal sound (paper sound) is generated. For this reason, conventionally, during conveyance in the return direction, the nip position of the conveyance roller pair is changed, the amount of protrusion of the corrugation member to the paper is reduced, and the pressure on the paper is reduced, thereby reducing the conveyance load and abnormal noise. An adjustment mechanism for preventing the above is known (see Patent Document 1).

JP 2008-019080 A

  However, the adjustment mechanism described above changes the position of one of the roller members of the transport roller pair, and the change requires a driving device such as a solenoid or a motor, and thus the structure is complicated. In addition, it is necessary to secure a space for moving the roller member and a space for installing the driving device, which hinders downsizing of the sheet conveying device. Furthermore, since high-cost parts, such as a drive device, are required, it is not preferable also in terms of cost.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a mechanism that can impart an appropriate waist to a sheet member such as paper at the time of discharge and that does not cause a load on the sheet member when the sheet member is conveyed in a direction to return to the inside. Another object of the present invention is to provide a sheet conveying apparatus that can be realized with a simple configuration and an image forming apparatus including the sheet conveying apparatus.

  A sheet conveying apparatus according to one aspect of the present invention includes a conveying roller pair and a waist member. The pair of transport rollers is disposed in a transport path that reaches the sheet discharge port, is rotationally driven in the forward and reverse directions, and transports the sheet member in the transport path while sandwiching the sheet member. The waist member is provided swingably at a position spaced apart in a width direction orthogonal to a conveyance direction of the sheet member conveyed along the conveyance path with respect to a nip portion of the conveyance roller pair, and the conveyance path The sheet member is pressed by pressing the sheet member conveyed. The seating member presses the sheet member that is swung toward the ejection direction side and passes through the seating member when the tip of the sheet member conveyed in the ejection direction toward the sheet ejection port comes into contact with the seating member. The sheet member is disposed at a first position where it can be seated, and is swung toward the return direction side by the contact of the sheet member conveyed in the return direction opposite to the discharge direction by the transport roller pair. It arrange | positions in the 2nd position which cancels | releases the seating with respect to the said sheet | seat member which passes a member.

  An image forming apparatus according to another aspect of the present invention includes the sheet conveying device and a reverse conveying unit. The reverse conveyance unit conveys the sheet member conveyed in the return direction by the conveyance roller pair of the sheet conveyance device to the upstream side of the image forming unit.

  According to the present invention, a mechanism that can impart an appropriate waist to a sheet member, such as paper, at the time of discharge and that does not cause a transport load on the sheet member when the sheet member is transported in a direction to return to the inside is simple. It is possible to realize with a simple configuration.

FIG. 1 is a perspective view showing an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an internal configuration of the image forming apparatus. FIG. 3 is an enlarged cross-sectional view of the periphery of the paper discharge unit included in the image forming apparatus. FIG. 4 is a schematic diagram illustrating a configuration of the paper discharge unit when the paper discharge unit is viewed from the paper discharge port side. FIG. 5 is a perspective view showing a corrugation member and a lever member provided in the paper discharge unit. FIG. 6 is a view showing the corrugation member and the lever member, and shows a state in which the corrugation member is arranged at the reference position. FIG. 7 is a diagram illustrating the corrugation member and the lever member, and shows a state in which the corrugation member is disposed at the first position and the lever member is disposed at the third position. FIG. 8 is a view showing the corrugation member and the lever member, and shows a state in which the lever member abuts on the upper surface of the sheet and presses downward. FIG. 9 is a diagram showing the corrugation member and the lever member, and shows a state in which the printing paper discharged from the lever member is pushed downward. FIG. 10 is a diagram illustrating the corrugation member and the lever member, and shows a state in which the rear end of the printing paper is stopped while being sandwiched by the discharge roller pair. FIG. 11 is a diagram illustrating the corrugation member and the lever member, and shows a state in which the corrugation member is rotated from the reference position to the second position when the printing paper is reversely fed.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The following embodiments are examples embodying the present invention, and do not limit the technical scope of the present invention.

  The configuration of the image forming apparatus 10 will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the image forming apparatus 10 is a so-called in-body discharge type multifunction machine, and includes various functions such as a printer, a copier, a FAX apparatus, and a scanner.

  The image forming apparatus 10 includes an image reading unit 12, an image forming unit 14, and two paper feeding devices 27 and 28.

  The image reading unit 12 is provided on the upper part of the image forming apparatus 10. The image reading unit 12 performs processing for reading an image of a document, and includes a document cover 24 and an ADF 13. The image reading unit 12 reads the image data of the document set on the document table 23 (see FIG. 1) or the document conveyed by the ADF 13. Then, the read image data is sent to the image forming unit 14. In FIG. 1, the document cover 24 is not shown.

  The image forming unit 14 is provided below the image reading unit 12. The image forming unit 14 performs processing for forming an image on the printing paper P (an example of the sheet member of the present invention) based on an electrophotographic system. The image forming unit 14 forms an image on the printing paper P based on the image data read by the image reading unit 12 or image data input from the outside. The image forming unit 14 performs single-sided printing processing (single-sided image forming processing) for forming an image only on one side of the printing paper P or printing paper according to a preset printing mode (single-sided printing mode or double-sided printing mode). One of double-sided printing processing (double-sided image forming processing) for forming images on both sides of P is performed.

  When the single-sided printing process is performed, the image forming unit 14 discharges the printing paper P on which the image is formed on one side to the paper discharge tray 21 </ b> A of the paper discharge space 21. The paper discharge space 21 is a space formed between the image forming unit 14 and the image reading unit 12. On the other hand, when the double-sided printing process is performed, the image forming unit 14 switches back the printing paper P on which the image is formed on one side and then sends it to the reverse conveyance path 39 described later, and again conveys it to the image forming position. An image is formed on the opposite side from the surface. Thereafter, the printing paper P on which images are formed on both sides is discharged to the paper discharge tray 21A.

  Two paper feeding devices 27 and 28 arranged in two upper and lower stages are provided below the image forming unit 14. The paper feeding devices 27 and 28 include a paper feeding tray 22 and a paper feeding mechanism 15, and the paper feeding mechanism 15 takes out the printing paper P stored in the paper feeding tray 22 one by one and puts it in the vertical conveyance path 26. To feed.

  As shown in FIG. 2, the image forming unit 14 mainly controls the casing 29, the image transfer unit 18, the fixing unit 19, the paper discharge unit 30 (an example of the sheet conveying apparatus of the present invention), and the image forming apparatus 10. And a control unit (not shown) for controlling. These are provided inside the housing 29. Further, the image forming apparatus 10 includes a transport motor and a discharge motor (both not shown).

  As shown in FIG. 2, the image forming unit 14 is formed with a vertical conveyance path 26 extending upward from the paper feeding mechanism 15 of the paper feeding devices 27 and 28. The vertical conveyance path 26 is formed on the right side surface inside the housing 29 and extends in the up-down direction 6 along the right side surface. The vertical conveyance path 26 is formed in a section that reaches a sheet discharge port 37 (an example of a sheet discharge port of the present invention) via a junction point T2, a transfer roller 35, a fixing unit 19, and a branch point T1, which will be described later. The printing paper P that has passed through the fixing unit 19 passes through the vertical conveyance path 26 and is discharged to the outside from the paper discharge port 37.

  In the housing 29, a reverse conveyance path 39 is formed on the right side of the vertical conveyance path 26. The reverse conveyance path 39 branches from a branch point T1 in the middle of a discharge path 26A described later and reaches a junction T2 of the vertical conveyance path 26. The junction T2 is located on the upstream side of the image transfer unit 18 described later in the vertical conveyance path 26. A plurality of conveyance roller pairs 40 are provided in the reverse conveyance path 39, and the printing paper P is conveyed by the conveyance roller pairs 40 along the reverse conveyance path 39 toward the junction T <b> 2. In addition, the reverse conveyance part of this invention is implement | achieved by the reverse conveyance path 39 and the some conveyance roller pair 40. FIG.

  An image transfer unit 18 is provided above the paper feeding device 27. The image transfer unit 18 performs an image transfer process on the printing paper P conveyed through the vertical conveyance path 26. Specifically, the image transfer unit 18 transfers the toner image to the printing paper P using a developer containing toner based on the input image data. As shown in FIG. 2, the image transfer unit 18 includes a photosensitive drum 31, a charging unit 32, a developing unit 33, an LSU (Laser Scanning Unit) 34, a transfer roller 35, and a cleaning unit 36. ing. When the printing paper P passes through the nip portion between the transfer roller 35 and the photosensitive drum 31, the toner image is transferred to the printing paper P by the transfer roller 35.

  The fixing unit 19 is disposed on the downstream side (that is, the upper side) in the transport direction of the printing paper P with respect to the image transfer unit 18. The printing paper P to which the toner image has been transferred is conveyed to the fixing unit 19. The fixing unit 19 includes a heating roller 41 and a pressure roller 42, and further includes conveyance guides 62 and 63, a lower conveyance guide 64, and a rotation roller 66, which will be described later, and is unitized as one device. Yes. The fixing unit 19 fixes the toner image transferred to the printing paper P onto the printing paper P by heat. The fixed printing paper P is conveyed toward the paper discharge port 37.

  A paper discharge port 37 through which the printing paper P is discharged is formed at the end of the vertical conveyance path 26. Hereinafter, for convenience of explanation, a path from the outlet on the downstream side of the fixing unit 19 to the sheet discharge port 37 in the vertical conveyance path 26 is referred to as a discharge path 26A. That is, the paper discharge port 37 is formed at the end of the discharge path 26A. The sheet discharge port 37 is formed in a side wall 29A that defines the right side of the sheet discharge space 21, and is an opening that is elongated in the width direction D20 (see FIG. 4) of a curved path 26A2 described later. Here, the width direction D20 is a direction orthogonal to the transport direction of the printing paper P transported through the curved path 26A2.

  The discharge path 26 </ b> A guides the printing paper P on which the image is fixed by the fixing unit 19 to the paper discharge port 37. The discharge path 26A is formed in a curved shape that extends upward from the fixing unit 19 and then curves toward the paper discharge port 37 in the vicinity of the branch point T1 on the way. The discharge path 26A is formed by a plurality of conveyance guides 62 to 65 (see FIG. 3). The conveyance guides 62 and 63 are provided along the straight path 26A1 extending obliquely from the fixing unit 19 to the branch point T1 in the discharge path 26A (see FIG. 2). Further, the conveyance guides 64 and 65 are provided along the curved path 26A2 from the branch point T1 to the sheet discharge port 37 in the discharge path 26A.

  As shown in FIG. 3, the paper discharge unit 30 is provided in the vicinity of the paper discharge port 37. The paper discharge unit 30 includes a lower conveyance guide 64, an upper conveyance guide 65, four discharge roller pairs 25 (an example of a conveyance roller pair of the present invention), a rotating roller 66, and a corrugation member 70 (an example of a waist member of the present invention). ), A lever member 80 (an example of the pressing member of the present invention), and the like.

  The curved path 26A2 (an example of the transport path of the present invention) in the discharge path 26A is formed by the lower transport guide 64 and the upper transport guide 65. That is, the paper discharge unit 30 has the curved path 26A2. The lower conveyance guide 64 has a lower guide surface 641 of the curved path 26A2. The upper conveyance guide 65 has an upper guide surface 651 of the curved path 26A2. In the present embodiment, the upper conveyance guide 65 protrudes so as to protrude to the left side from the terminal portion of the lower conveyance guide 64 and the paper discharge port 37. A lever member 80 is provided at the protruding portion.

  A rotating roller 66 is rotatably provided on the lower conveyance guide 64. The rotating roller 66 can reduce the contact friction received from the lower conveyance guide 64 when conveying the printing paper P in the discharge path 26A, and the printing paper P is smoothly conveyed.

  Each discharge roller pair 25 is provided in the vicinity of the sheet discharge port 37. The discharge roller pair 25 is rotated in the forward rotation direction to discharge the printing paper P from the paper discharge port 37 to the external paper discharge tray 21A. The discharge roller pair 25 is a pair of rollers configured by a drive roller 25A and a driven roller 25B that are in pressure contact with each other. The driving roller 25A and the driven roller 25B are arranged to face each other so as to sandwich the curved path 26A2 from the up-down direction 6.

  The driving roller 25A is rotatably supported by the upper conveyance guide 65. The paper discharge unit 30 is provided with four drive rollers 25 </ b> A corresponding to the four discharge roller pairs 25. The four drive rollers 25A are attached to a common rotating shaft 251. Bi-directional (forward / reverse direction) rotational driving force is transmitted to the rotating shaft 251 from the discharging motor (not shown). For this reason, the drive roller 25A is rotationally driven in the forward rotation direction or the reverse rotation direction according to the input rotational driving force.

  The driven roller 25B is rotatably supported by the lower conveyance guide 64. The driven roller 25 </ b> B is supported in a state of being housed in a housing portion 64 </ b> A formed at the terminal portion of the lower conveyance guide 64. The driven roller 25B is urged toward the driving roller 25A by an elastic member (not shown) such as a coil spring. For this reason, the driven roller 25B is always pressed against the surface of the driving roller 25A with an appropriate elastic biasing force, whereby the nip portion can hold the printing paper P between the driving roller 25A and the driven roller 25B. Is formed. When the driving roller 25A is driven to rotate, the driven roller 25B is also driven by the contact friction of the nip portion.

  As shown in FIG. 4, in the paper discharge unit 30, four discharge roller pairs 25 are provided at predetermined intervals along the width direction D20 of the curved path 26A2. Specifically, four discharge roller pairs 25 are provided at equal intervals along the width direction D20 of the curved path 26A2. Accordingly, four drive rollers 25A and four driven rollers 25B are provided. The rotary shaft 251 extending in the width direction D20 is rotatably supported by a bearing portion (not shown) provided on the back side of the transport surface of the upper transport guide 65 at both ends in the axial direction. Four drive rollers 25A are fixed. Further, four accommodating portions 64A that are equally spaced along the width direction D20 are formed at the end portion of the lower conveyance guide 64, and the rotation shafts of the driven rollers 25B on both side walls of each accommodating portion 64A. 252 is rotatably supported. The width direction D20 corresponds to the front-rear direction 7 shown in FIG.

  When the rotation direction of the discharge motor (not shown) is controlled by the control unit (not shown), the four discharge roller pairs 25 are nip portions that are pressure contacts between the driving roller 25A and the driven roller 25B. The printing paper P is nipped and conveyed in either the discharge direction D11 or the return direction (switchback direction) D12 shown in FIG. The discharge direction D11 is a direction in which the print paper P in the discharge path 26A is directed to the paper discharge port 37. The return direction D12 is a direction opposite to the discharge direction, and is a direction in which the printing paper P in the discharge path 26A is directed to the reverse conveyance path 39. For example, the printing paper P that has passed through the fixing unit 19 and is conveyed to the discharge path 26A is discharged toward the paper discharge port 37 by the discharge roller pair 25 that is rotated in the normal rotation direction by the normal rotation drive of the discharge motor. It is conveyed in the direction D11. Further, the printing paper P once transported to the discharge path 26A is transported in the return direction D12 toward the reverse transport path 39 by the discharge roller pair 25 rotated in the reverse rotation direction by the reverse rotation driving of the discharge motor ( Will be sent back). Here, the normal rotation direction is the rotation direction of the discharge roller pair 25 that is rotated when the print paper P is discharged from the paper discharge port 37. The reverse rotation direction is a rotation direction opposite to the normal rotation direction, and is rotated when the printing paper P is conveyed (reversely fed) in the reverse direction to return to the reverse conveyance path 39 during the double-sided printing process. This is the rotation direction of the discharge roller pair 25 to be rotated.

  When single-sided printing processing is performed in the image forming unit 14, the printing paper P on which the toner image has been transferred to one side by the image transfer unit 18 passes through the fixing unit 19 and is then transported to the discharge path 26 </ b> A and four discharge rollers. Each of the pairs 25 is discharged from the paper discharge port 37 to the discharge tray 21A of the discharge space 21.

  On the other hand, when double-sided printing processing is performed in the image forming unit 14, the printing paper P on which an image is formed on one side passes through the fixing unit 19 and is conveyed to the discharge path 26A, and then reversely conveyed through the discharge path 26A. Then, it is sent to the reverse conveyance path 39. Specifically, the discharge roller pair 25 is stopped in a state where the leading end in the discharge direction D11 of the printing paper P on which an image is formed on one side is exposed to the outside from the paper discharge port 37. At this time, the rear end of the discharge direction D11 of the printing paper P is held in a state of being sandwiched by the discharge roller pair 25. Thereafter, the discharge roller pair 25 is rotated in the reverse rotation direction by the reverse rotation drive of the discharge motor (not shown). As a result, the printing paper P is conveyed in the return direction D12 through the discharge path 26A. That is, the printing paper P is fed back through the discharge path 26A.

  As shown in FIGS. 3 and 4, the corrugation member 70 and the lever member 80 are provided on the upper conveyance guide 65.

  The corrugation member 70 is provided at a position (see FIG. 4) that is separated from the drive roller 25A of the discharge roller pair 25 in the width direction D20 of the curved path 26A2, and is supported by the upper conveyance guide 65 so as to be swingable. . The corrugation member 70 contacts the printing paper P conveyed in the discharge direction D11 through the curved path 26A2 and presses the printing paper P downward, thereby attaching the waist to the printing paper P. In this embodiment, as shown in FIG. 4, one corrugation member 70 is provided between the drive rollers 25A of the four discharge roller pairs 25, and three corrugation members 70 are provided in total. Specifically, the corrugation member 70 is provided in the middle of the interval between the adjacent discharge roller pairs 25 when viewed from the paper discharge port 37 side. For this reason, the printing paper P conveyed through the curved path 26A2 is pressed downward by the corrugation member 70, whereby a wavy undulation that undulates in the width direction D20 is formed along the conveyance direction of the printing paper P. The In this way, forming the corrugated undulations on the printing paper P to make the printing paper P firmer is also referred to as “stiffening”.

  In the present embodiment, the corrugation member 70 is supported so as to be swingable between a first position (position shown in FIG. 7) and a second position (position shown in FIG. 11) described later.

  As shown in FIG. 6, the first position is such that when the printing paper P is conveyed in the discharge direction D11 toward the paper discharge port 37, the leading end P1 of the printing paper P in the discharge direction D11 contacts the corrugation member 70. It is a position (position shown in FIG. 7) that is in contact with and swung toward the discharge direction D11 when the corrugation member 70 receives the force in the discharge direction D11. Specifically, this is a position where the corrugation member 70 swings in the discharge direction D11 side due to the contact of the leading end P1 of the printing paper P, and then stops in contact with a stopper 652 described later. In the state of being arranged at the first position, the corrugation member 70 contacts the upper surface of the printing paper P and presses the printing paper P downward. FIG. 7 shows a state in which the lower end 721 of the pressing portion 72 of the corrugation member 70 is disposed below the lower surface of the printing paper P. However, in actuality, the lower end 721 is in contact with the printing paper P. The portion is bent downward, and the portion is deformed into a valley shape.

  Further, as shown in FIG. 10, the second position is such that the trailing edge P2 of the printing paper P (the end portion in the return direction D12) is sandwiched by the discharge roller pair 25, and the printing paper P in the return direction D12. The rear end P2 of the printing paper P abuts on the corrugation member 70 when the paper is conveyed, and the corrugation member 70 receives the force in the return direction D12 and is swung to the return direction D12 side. (Position shown in FIG. 11). In the state where the corrugation member 70 is disposed in the second position, the pressing of the corrugation member 70 to the printing paper P becomes extremely weak, and the above-mentioned back-up due to the pressing of the printing paper P does not substantially occur. In other words, in a state where the corrugation member 70 is disposed at the second position, the pressing on the upper surface of the printing paper P does not occur, and the waisting by the corrugation member 70 is substantially released.

  Hereinafter, the configuration of the corrugation member 70 will be described. Corrugation member 70 is a resin molded product, and is formed of, for example, polyacetal resin. As shown in FIG. 3, the corrugation member 70 is provided on the upper conveyance guide 65. Further, as shown in FIG. 5, the corrugation member 70 includes a rotation shaft 71 that is pivotally supported by the upper conveyance guide 65, a pressing portion 72, and an arm portion 73, which are integrally configured. ing.

  The rotation shaft 71 is supported by a bearing portion (not shown) provided in the upper conveyance guide 65. The bearing portion is provided on the upper guide surface 651 of the upper transport guide 65, that is, the rotation shaft 71 is pivotally supported at a position above the upper guide surface 651 in the upper transport guide 65. Specifically, the upper guide surface 651 is formed with a slit (not shown) through which the sliding corrugation member 70 can pass. On both sides of the slit, a pair of support plates (not shown) are provided standing on the inner side of the upper guide surface 651. The bearing portion is formed on the pair of indicator plates, and a rotating shaft 71 is pivotally supported on the bearing portion. The rotation shaft 71 is supported at a position separated from the rotation shaft 251 of the drive roller 25A toward the return direction D12.

  The pressing portion 72 extends from the rotation shaft 71 toward the curved path 26A2, passes through the upper guide surface 651, and protrudes into the curved path 26A2. For this reason, the upper conveyance guide 65 is formed with a through opening (not shown) that penetrates the pressing portion 72. The corrugation member 70 is in a state where it does not receive an external force from the printing paper P conveyed through the curved path 26A2 (that is, it is not in contact with the printing paper P), which will be described later (see FIGS. 6, 9, and 10). (Position shown). Here, the reference position is a position defined between the first position (position shown in FIG. 7) and the second position (position shown in FIG. 11), and is pressed against the curved path 26A2. This is a position where the portions 72 intersect substantially vertically. When the printing paper P is conveyed along the curved path 26A2 in the discharge direction D11 with the corrugation member 70 disposed at the reference position, the front end P1 of the printing paper P is the side surface of the pressing portion 72 on the return direction D12 side. Abut.

  The arm portion 73 is a linear bar-like member that extends from the rotation shaft 71 toward the discharge direction D11 and extends in the discharge direction D11. As shown in FIG. 6, with the corrugation member 70 in the reference position, the corrugation member 70 extends obliquely upward at a gentle angle (about 5 degrees) toward the discharge direction D11.

  The distal end 731 of the arm portion 73 is engaged with the lever member 80 at the reference position, and specifically, the upper portion of the distal end 731 of the arm portion 73 is pressed downward by a later-described protruding piece 84 of the lever member 80. Engaged to attach. Accordingly, in a state where no external force is received from the printing paper P, the swing of the corrugation member 70 from the reference position to the first position is restricted by the protruding piece 84 of the lever member 80 at the reference position.

  As shown in FIG. 6, the upper conveyance guide 65 has a stopper 652 (stopper of the present invention) that stops the corrugation member 70 that is swung in the swing direction from the reference position toward the first position. An example of a member) is provided. The stopper 652 is in contact with the arm portion 73 when reaching the first position, and plays a role of restraining displacement above the arm portion 73. Specifically, the stopper 652 receives a force from the printing paper P that is conveyed in the discharge direction D11 through the curved path 26A2, and the corrugation member 70 is swung from the reference position to the first position (position shown in FIG. 7). Sometimes, the corrugation member 70 is stopped at the first position. That is, when the corrugation member 70 swings from the reference position toward the first position and reaches the first position, the arm portion 73 comes into contact with the stopper 652 and further upward swing is prevented. The

  As shown in FIGS. 5 and 6, the pressing portion 72 has an abutting portion 74 with which the leading end P <b> 1 of the printing paper P abuts at the reference position. The abutting portion 74 extends from the lower end 721 (lower end portion) of the pressing portion 72 in the return direction D12, and is an approximately triangular portion with the extending end formed in a tapered shape. The contact portion 74 has an inclined surface 741 (an example of a contact surface according to the present invention) inclined obliquely upward from the lower end 721 of the pressing portion 72 toward the return direction. The inclined surface 741 is a surface on which the leading end P1 of the printing paper P conveyed in the discharge direction D11 is in contact with the corrugation member 70 disposed at the reference position. At the reference position, the inclination angle of the inclined surface 741 is approximately 45 degrees.

  When the printing paper P is conveyed toward the discharge direction D11 along the curved path 26A2, and the leading end P1 contacts the inclined surface 741, as shown in FIG. 6, the discharge direction applied to the inclined surface 741 at that time. The force of D11 is divided into two component forces according to the inclination angle of the inclined surface 741. One of the first component forces F1 (see FIG. 6) acts in a direction perpendicular to the inclined surface 741, and the first component force F1 causes the corrugation member 70 to swing from the reference position toward the first position. Try to move. The first component force F1 at this time is greater than the force with which the protruding piece 84 of the lever member 80 presses the tip 731 of the arm portion 73 downward. For this reason, by receiving the first component force F1, the corrugation member 70 swings from the reference position to the first position. Also, the other second component force F2 of the two component forces acts as a force that directs the tip P1 obliquely downward along the inclined surface 741. By this second component force F2, the leading edge P1 of the printing paper P is directed to the nip portion of the discharge roller pair 25, and the printing paper P is guided to the nip portion.

  The size and size of each of the arm portion 73 and the contact portion 74 can be supported with the corrugation member 70 in equilibrium with the pressing portion 72 extending vertically downward at the reference position (position shown in FIG. 6). It is established as follows.

  The lever member 80 is provided in the upper conveyance guide 65 at a position separated from the corrugation member 70 in the discharge direction D11 and is supported by the upper conveyance guide 65 so as to be swingable. Specifically, the lever member 80 is provided at a position separated from the drive roller 25A toward the discharge direction D11. As described above, the upper conveyance guide 65 protrudes so as to protrude to the left side (the discharge direction D11 side) from the terminal portion of the lower conveyance guide 64 and the sheet discharge port 37, and a lever member is formed at the protruding portion. 80 is provided.

  The lever member 80 contacts the upper surface of the printing paper P that has been transported in the discharge direction D11 and passed through the corrugation member 70, and presses downward. Thereby, the momentum of the printing paper P discharged from the paper discharge port 37 can be attenuated by contact friction, and the rear end P2 of the printing paper P can be directed to the tray surface of the paper discharge tray 21A.

  In the present embodiment, as shown in FIG. 4, one lever member 80 is provided between the four discharge roller pairs 25, and three lever members 80 are provided in total. Specifically, the lever member 80 is provided in the middle of the interval between the adjacent discharge roller pairs 25 when viewed from the paper discharge port 37 side.

  In the present embodiment, the lever member 80 is supported so as to be swingable between a third position (position shown in FIG. 7) and a fourth position (position shown in FIG. 9) described later.

  As shown in FIG. 7, the third position is a position where the lever member 80 is spaced upward from the upper surface of the printing paper P exposed to the outside from the paper discharge port 37. Specifically, this is a position where a tip 821 of a lower arm portion 82 described later of the lever member 80 is disposed above the nip portion of the discharge roller pair 25. In the present embodiment, when the corrugation member 70 is swung to the first position by receiving a force from the printing paper P conveyed in the discharge direction D11, the lever member 80 moves to the first position side of the corrugation member 70. Swinging to the third position side in conjunction with swinging to. When the corrugation member 70 is disposed at the first position, the lever member 80 is supported by the corrugation member 70 disposed at the position so as to be maintained at the third position.

  Further, as shown in FIG. 9, the fourth position is a position where the upper surface of the printing paper P exposed to the outside from the paper discharge port 37 can be pressed downward. FIG. 8 shows a state in which the lever member 80 is in contact with the upper surface of the printing paper P when the rear end P2 of the printing paper P is sandwiched between the nip portions of the discharge roller pair 25. FIG. 9 shows a state in which the lever member 80 presses and pushes down the upper surface of the printing paper P when the printing paper P passes through the nip portion of the discharge roller pair 25.

  Hereinafter, the configuration of the lever member 80 will be described. The lever member 80 is a resin molded product and is formed in a bent shape as a whole in side view. The lever member 80 is made of, for example, polyacetal resin. As shown in FIG. 5, the lever member 80 includes a rotation shaft 81 that is pivotally supported by the upper conveyance guide 65, a lower arm portion 82, and an upper arm portion 83, which are integrally formed. It is configured.

  The rotation shaft 81 is supported by a bearing portion (not shown) provided inside the upper conveyance guide 65. In the present embodiment, the rotation shaft 81 is supported at a position above the upper guide surface 651 in the upper conveyance guide 65 and at a position separated from the rotation shaft 251 of the drive roller 25A in the discharge direction D11. Yes.

  As shown in FIGS. 5 and 6, the lower arm portion 82 extends obliquely downward in the return direction D <b> 12 from the rotation shaft 81 and penetrates the upper guide surface 651 and protrudes downward. For this reason, the upper transport guide 65 is formed with a through opening (not shown) that penetrates the lower arm portion 82. The lower arm portion 82 extends obliquely downward toward the paper discharge port 37 side. When the lever member 80 is disposed at the third position, the tip 821 of the lower arm portion 82 is disposed at a position separated from the upper surface of the printing paper P. Further, when the lever member 80 is disposed at the fourth position, the tip 821 of the lower arm portion 82 comes into contact with the upper surface of the printing paper P.

  The upper arm portion 83 extends obliquely upward from the rotation shaft 81 in the return direction D12. The upper arm 83 extends in a direction in which an angle formed with the lower arm 82 is substantially a right angle. On the protruding end side of the upper arm portion 83, a protruding piece 84 that can be engaged with the tip 731 of the arm portion 73 is formed integrally. The protruding piece 84 is formed in a plate shape in a side view and is bent toward the return direction D12 with respect to the upper arm portion 83. The protruding piece 84 extends beyond the top end 731 of the arm portion 73 toward the return direction D12. That is, the protruding piece 84 is disposed above the tip 731.

  In the present embodiment, a stopper 653 is provided in order for each of the lower arm portion 82 and the upper arm portion 83 to maintain a posture (see FIG. 6) extending toward the return direction D12. The stopper 653 is provided on the upper conveyance guide 65. The stopper 653 plays a role of holding the lever member 80 at the fourth position in a state where no external force is applied to the lever member 80. Specifically, the lever member 80 is subjected to a rotational moment to rotate clockwise in FIG. 6 due to the weight of the lower arm portion 82 and the upper arm portion 83. The lever member 80 tries to rotate in the same direction by this rotational moment, but the lever member 80 is restrained to the fourth position by the lower arm portion 82 coming into contact with the stopper 653.

  Hereinafter, operations of the corrugation member 70 and the lever member 80 will be described with reference to FIGS. 6 to 11.

  When the printing paper P is not conveyed to the curved path 26A2, as shown in FIG. 6, the corrugation member 70 is disposed at the reference position, and the lever member 80 is disposed at the fourth position. Still in position. In this state, when the printing paper P is conveyed to the curved path 26A2 and the leading end P1 thereof contacts the inclined surface 741 of the corrugation member 70, the corrugation member 70 is swung from the reference position to the first position. A component force F1 is applied. By receiving the first component force F1, the corrugation member 70 swings in the clockwise direction in FIG. 7 and is disposed at the first position. The stopper 652 holds the first position. In the first position, the lower end 721 of the pressing portion 72 of the corrugation member 70 is positioned below the nip portion of the discharge roller pair 25, whereby the printing paper P is pressed downward by the corrugation member 70. As a result, wave-like undulations that undulate in the width direction D20 are formed on the printing paper P during conveyance in the discharge direction D11 by the discharge roller pair 25.

  Further, as the corrugation member 70 swings to the first position, the arm portion 73 is displaced upward, and an upward force F31 is applied from the tip 731 of the arm portion 73 to the protruding piece 84 of the lever member 80. . As a result, as shown in FIG. 7, the protruding piece 84 is displaced upward, and the lever member 80 arranged at the fourth position swings counterclockwise and is arranged at the third position. The When the corrugation member 70 is in the first position and the lever member 80 is in the third position, the lower arm 82 of the lever member 80 is spaced upward from the printing paper P, so the lower arm The portion 82 does not interfere with the print paper P exposed from the paper discharge port 37.

  Thereafter, as shown in FIG. 8, when the rear end P2 of the printing paper P passes through the corrugation member 70, the force from the printing paper P acting on the corrugation member 70 is lost, and the corrugation member 70 By its own weight, it swings from the first position to the reference position side and tries to return to the reference position. At this time, the upper force F31 applied to the protruding piece 84 by the tip 731 of the arm portion 73 is lost, and the lever member 80 swings from the third position in the clockwise direction of FIG. , To the fourth position side. As a result, the tip 821 of the lower arm portion 82 comes into contact with the upper surface of the printing paper P exposed from the paper discharge port 37, and a force F32 that presses the printing paper P downward is applied to the upper surface. In the state where the trailing edge P2 of the printing paper P is sandwiched by the discharge roller pair 25, the trailing edge P2 of the printing paper P is caused by the waved undulations formed on the printing paper P and the nip force by the discharging roller pair 25. The side portion is not immediately pushed downward by the force F32, and maintains the horizontal state shown in FIG.

  When the trailing edge P2 of the printing paper P exits the discharge roller pair 25, as shown in FIG. 9, the lever member 80 further swings in the clockwise direction, reaches the fourth position, and is stopped by the stopper 653. Held in that position. At this time, the momentum of the printing paper P discharged from the paper discharge port 37 is attenuated by the contact friction with the tip 821 of the lower arm portion 82 and the force that pushes the printing paper P downward. For this reason, it is possible to prevent the printing paper P from jumping out of the paper discharge port 37 with vigorous force. Further, the rear end P2 of the printing paper P can be directed to the tray surface of the paper discharge tray 21A, and the stacking state and alignment of a plurality of printing papers on the paper discharge tray 21A are improved.

  Further, when the double-sided printing process is performed, as shown in FIG. 10, the conveyance of the printing paper P is temporarily stopped with the trailing edge P2 of the printing paper P being sandwiched by the discharge roller pair 25, and then the return is performed. It is conveyed in the direction D12. In this case, if the squeezing by the pressing of the corrugation member 70 is continued during conveyance in the return direction D12, a load is applied to the printing paper P during conveyance in the return direction D12, and the printing paper P is smoothly conveyed. There is a risk that the printing paper P may be jammed. Further, when the wave shape formed on the printing paper P by the back-up during the conveyance in the return direction D12 returns to the original, abnormal noise (paper sound) is generated. However, in this embodiment, since the corrugation member 70 is configured as described above, when the printing paper P is conveyed in the return direction D12, the rear end P2 of the printing paper P is located on the side surface of the pressing portion 72. At that time, the force F33 in the return direction D12 is applied to the pressing portion 72 at that time. This force F33 is displaced to the second position (position shown in FIG. 11) by swinging the corrugation member 70 arranged at the reference position (position shown in FIG. 10) counterclockwise in FIG. Let In the second position, the lower end 721 of the pressing portion 72 of the corrugation member 70 is in contact with the upper surface of the printing paper P, but the pressing force is hardly applied, and the lumping by the corrugation member 70 is not performed. Therefore, no corrugation is formed on the printing paper P. For this reason, even when the printing paper P is reversely fed through the curved path 26A2 during the double-sided printing process, the printing paper P is smoothly conveyed without causing the load or the abnormal noise.

  In the above-described embodiment, the example in which the corrugation member 70 and the lever member 80 are provided between each of the four discharge roller pairs 25 has been described. However, the number and positions of the corrugation members 70 and the lever members 80 are the same as those described above. The configuration is not limited to the embodiment. For example, the configuration may be such that the corrugation member 70 and the lever member 80 are provided only between the two discharge roller pairs 25 disposed on the center side in the width direction D20, or disposed on both outer sides in the width direction D20. Alternatively, the corrugation member 70 and the lever member 80 may be provided only inside the discharge roller pair 25.

  In the above-described embodiment, the paper discharge unit 30 provided with the corrugation member 70 and the lever member 80 is illustrated. However, the paper discharge unit 30 may include at least the corrugation member 70.

  In the above-described embodiment, the configuration in which the corrugation member 70 is provided in the upper conveyance guide 65 is illustrated, but the corrugation member 70 may be provided in the lower conveyance guide 64.

  Further, in the above-described embodiment, in the double-sided printing process, the conveyance of the printing paper P is temporarily stopped in a state where the trailing edge P2 of the printing paper P is sandwiched by the discharge roller pair 25, and then the conveyance in the return direction D12. However, the present invention is not limited to such an embodiment. For example, in the double-sided printing process, the rear end P2 of the printing paper P is sandwiched by the discharge roller pair 25 and conveyed in the return direction D12 while being in contact with the lower end 721 of the pressing portion 72 of the corrugation member 70. The present invention is also applicable to examples. In this case, the corrugation member 70 when the printing paper P is temporarily stopped is disposed at the first position. When the printing paper P is conveyed in the return direction D12, a force in the return direction D12 is applied to the pressing portion 72 by contact friction between the upper surface of the printing paper P and the lower end 721 of the pressing portion 72. By receiving this force, the corrugation member 70 arranged at the first position is swung in the counterclockwise direction of FIG. 10 and is displaced to the second position via the reference position.

10: Image forming apparatus 25: Discharge roller pair 25A: Drive roller 26: Vertical conveyance path 26A2: Curved path 30: Paper discharge unit 37: Paper discharge port 64: Lower conveyance guide 65: Upper conveyance guide 652: Stopper 653: Stopper 70: Corrugation member 71: Rotating shaft 72: Pressing portion 73: Arm portion 74: Abutting portion 741: Inclined surface 80: Lever member 81: Rotating shaft 82: Lower arm portion 83: Upper arm portion 84: Projection piece D11: discharge direction D12: return direction D20: width direction

Claims (10)

A conveying roller pair that is arranged in a conveying path that reaches the sheet discharge port, is rotationally driven in the forward and reverse directions, and sandwiches and conveys the sheet member in the conveying path;
The sheet that is swingably provided at a position separated in the width direction perpendicular to the conveyance direction of the sheet member conveyed along the conveyance path with respect to the nip portion of the conveyance roller pair, and is conveyed through the conveyance path A waisted member that sits against the sheet member by pressing the member,
The waist member is
When the leading end of the sheet member conveyed in the discharge direction toward the sheet discharge port comes into contact with the sheet member, the sheet member is swung toward the discharge direction and presses the sheet member passing through the waist member to be seated. The sheet which is disposed at one position and is swung toward the return direction side by the contact of the sheet member conveyed in the return direction opposite to the discharge direction by the conveyance roller pair and passes through the waist member. A sheet conveying device disposed at a second position for releasing the seating on the member.   The sheet conveying apparatus according to claim 1, further comprising a stopper member that stops the waist member that swings toward the first position at the first position. The transport path is formed by an upper transport guide and a lower transport guide that are vertically separated from each other,
The waist member includes a rotation shaft supported at a position above the guide surface of the upper conveyance guide, and extends from the rotation shaft to the conveyance path side so as to protrude into the conveyance path and contact the sheet member. The sheet conveying device according to claim 1, further comprising: a pressing portion that can be pressed. The waist member is a position defined between the first position and the second position in a state in which no external force is received from the sheet member, and the reference where the pressing portion intersects the conveyance path Placed in position,
4. The sheet conveyance according to claim 3, wherein the pressing portion includes a contact surface on which a front end of the sheet member conveyed in the discharge direction can be contacted in a state where the waist member is disposed at the reference position. apparatus.   The contact surface receives a force received when the front end of the sheet member comes into contact, a first component force that swings the seating member to the first position, and a front end of the sheet member to the pair of conveying rollers. The sheet conveying apparatus according to claim 4, wherein the sheet conveying device is an inclined surface that is divided into a second component force directed toward the nip portion. The waist member further has an arm portion extending from the waist rotation shaft to the discharge direction side,
The sheet conveying device according to claim 2, wherein the stopper member abuts on the arm portion and stops the waist member at the first position. A plurality of the transport roller pairs are provided side by side in the width direction of the transport path,
The sheet conveying apparatus according to claim 1, wherein the waist member is provided in the middle of the interval between adjacent pairs of conveying rollers.   The seat member is swingably provided at a position separated from the waist member toward the discharge direction, and the upper surface of the sheet member is lowered downward after the rear end of the sheet member in the discharge direction passes through the waist member. The sheet conveying apparatus according to claim 1, further comprising a pressing member for pressing.   The pressing member can swing in conjunction with the swinging of the waist member toward the first position, and is exposed from the sheet discharge port by the waist member disposed at the first position. Further, the third member is supported at a third position spaced upward from the upper surface of the seat member, and the third member is moved along with the seat member passing through the waist member and swinging the seat member toward the second position side. The sheet conveying device according to claim 8, wherein the support by the waist member at a position is released and the upper surface of the sheet member swings toward a fourth position where the upper surface can be pressed. A sheet conveying device according to any one of claims 1 to 9,
An image forming apparatus comprising: a reverse conveying unit that conveys the sheet member conveyed in the return direction by the conveying roller pair of the sheet conveying device to an upstream side of the image forming unit.

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