JP5858742B2 - Sheet conveying apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet conveying device and an image forming apparatus, and more particularly to a configuration of a skew feeding correction unit that corrects skew feeding of a sheet.

  2. Description of the Related Art Conventionally, image forming apparatuses such as copying machines, printers, and facsimiles are provided with an image forming unit and a sheet conveying device that conveys a sheet to the image forming unit by a conveying roller. By the way, in the conventional image forming apparatus, the sheet may be skewed when the sheet is conveyed due to deformation of the conveying roller or misalignment of the conveying roller. Here, in the image forming apparatus, the accuracy of the image forming position with respect to the sheet is greatly influenced by the position of the sheet with respect to the image forming unit. Therefore, it is an important image quality factor to accurately align the position of the sheet with respect to the image forming unit. ing.

  In view of this, in the conventional image forming apparatus, a skew feeding correction unit is provided in the sheet conveying device, and the skew feeding correction unit corrects the skew of the sheet to improve the image forming position accuracy. As such a skew correction unit, for example, a shutter that is biased in the direction opposite to the sheet conveying direction by a spring or the like is provided, and the leading end of the sheet is brought into contact with the shutter (Patent Document 1). ). In such a skew correction unit of the shutter system, the leading edge of the sheet is abutted against the abutting portion of the shutter member positioned perpendicular to the sheet conveyance direction, and the leading edge of the sheet is caused to follow the abutting portion. Thus, the skew of the sheet is corrected.

  FIG. 8 is a diagram illustrating a skew correction unit using such a conventional shutter system. As shown in FIG. 8, the skew feeding correction portion is provided with a plurality of shutter members 51 that are arranged in the width direction orthogonal to the sheet conveyance direction and that can rotate around the registration roller shaft 53. In FIG. 8, 54 is a plurality of registration rollers provided in the width direction, 52 is a registration roller shaft, 55 is a plurality of registration rollers provided in the width direction and press-contacts with the registration roller 54 so as to be able to come into contact with and away from it, Is the axis. The shutter member 51 is provided between the resist rollers 55 and is rotatable about the resist roller shaft 53. The shutter member 51 is connected by a connecting member 56 and is configured to rotate integrally.

  Here, the shutter member 51 includes a contact portion 51a that contacts the sheet, and until the sheet P is conveyed, the contact portion 51a is provided with the registration roller pair 54, as shown in FIG. The home position is located upstream of the nip portion 55 in the sheet conveying direction. When the shutter member 51 is at the home position, the shutter member 51 is opposite to the sheet conveying direction in which the conveyed sheet P can be locked by the own weight of the shutter member 51 and the connecting member 56 and the biasing spring 57. It has an urging force F.

  When the sheet P is conveyed by the intermediate conveyance roller pairs 3 and 4, the leading end of the sheet P abuts on the abutting portion 51 a of the shutter member 51. Here, the sheet P is temporarily locked by the urging force F applied to the shutter member 51 by the urging spring 57 or the like when the leading end abuts on the abutting portion 51a. Then, by being locked in this manner, when the sheet P is further conveyed by the intermediate conveyance roller pair 3 and 4 after that, the sheet P eventually becomes a space V surrounded by the intermediate guides 14 and 15 constituting the conveyance path. Curve inside to form a loop.

Here, when the loop is formed in this manner, the leading edge of the sheet abuts against the abutting portion 51 a of the shutter member 51 in the entire width direction of the sheet due to the strength of the sheet itself, and the leading edge of the sheet eventually becomes parallel to the shutter member 51. The skew of the sheet P is corrected. After the skew is corrected in this way, when the conveying force F _p of the contact with the sheet P to the shutter member 51 is greater than the biasing force F of the shutter member 51, connected to the shutter member 51 member 56 is a sheet conveying It rotates in the direction of retreating from the road. As a result, the sheet P reaches the nip portion of the pair of registration rollers 54 and 55 in a state where the skew is corrected.

  Thereafter, when the sheet P is conveyed by the pair of registration rollers 54 and 55, the shutter member 51 is retracted from the sheet conveying path to a retracted position where the sheet is allowed to pass as shown in FIG. 9B. Rotate. Thus, the sheet P is conveyed to the downstream image forming unit through the conveyance path formed by the upper transfer guide 16 and the lower transfer guide 17 without being interrupted by the shutter member 51.

JP-A-9-183539

  By the way, in recent years, a thin sheet such as a thin paper having a smaller basis weight has been used in an image forming apparatus in response to an increase in user's awareness of the environment. Kosi is weak. For this reason, in a sheet conveying apparatus and an image forming apparatus provided with the same, when correcting skew feeding of a thin sheet by a skew feeding correction unit using a conventional shutter method, the stiffness of the sheet is weak. May bend following the contact portion of the shutter member.

  FIG. 10 is a diagram illustrating a state when the skew correction of a thin sheet is corrected by the skew correction unit using the shutter method. Here, in the conventional skew correction portion, the ideal sheet P conveyance path after the leading edge passes through the nip portion of the registration roller pair 54 and 55 is the nip line 58 of the registration roller pair 54 and 55.

  However, in the case of the thin sheet P having a weak stiffness, as described above, the leading end may follow without leaving the contact portion 51a of the shutter member 51 that is retracted from the sheet conveyance path. As a result, the leading edge of the sheet P follows the conveyance path 59 that is bent toward the retracting direction of the shutter member 51 rather than the ideal conveyance path 58, and the leading edge of the sheet is bent. . Note that this phenomenon is more likely to occur in a sheet with a smaller basis weight.

  Here, when the leading end of the sheet is bent in this way, if the sheet is conveyed in this state, the leading end of the sheet P is detached from the contact portion 51a before and after the shutter member 51 is rotated to the retracted position. At this time, noise such as paper splashing may occur from the front end of the sheet P. In addition, even if the shutter member 51 is rotated to the retracted position, the leading edge of the sheet may not be detached from the contact portion 51a. In this case, the leading edge of the sheet P is extremely deformed in the retracting direction of the shutter member 51, and In some cases, the edge may be damaged or the sheet may be bent.

  Accordingly, the present invention has been made in view of such a current situation, and provides a sheet conveying apparatus and an image forming apparatus that can reduce noise and deformation of the leading end of the sheet when passing through the skew correction unit. It is for the purpose.

The present invention provides a sheet conveyance device having a skew correction unit that corrects the skew of a sheet, and the skew correction unit is arranged with a gap in the width direction perpendicular to the first rotating body and the sheet conveyance direction. A rotating body pair having a plurality of second rotating bodies and a nip portion of the rotating body pair that is rotatably provided between the plurality of second rotating bodies and biased in a direction opposite to the sheet conveying direction. The sheet is brought into contact with the sheet toward the rotating body pair upstream of the sheet conveying direction to correct skewing, and the sheet is rotated by resisting biasing force by being pressed by the sheet whose skewing is corrected. A shutter member that enters the nip portion of the sheet, and the shutter member is positioned upstream of the nip portion of the rotating body pair in the sheet conveying direction and faces the rotating body pair until the sheet comes into contact with the shutter member. A contact portion that contacts, and the contact portion Located in remote shutter member rotation direction upstream, when the sheet reaches the nip portion of the pair of rotating members while rotating the shutter member to press the contact portion, so that the sheet is separated from the contact portion A pressing portion that presses the sheet, and when the pressing portion is viewed from the axial direction of the second rotating body, a protruding position in which a tip protrudes outward from the second rotating body, than the projection position is characterized in movable der Rukoto into a retracted position inside of the shutter member.

  As in the present invention, when the sheet reaches the nip portion of the pair of rotating bodies while rotating the shutter member, the sheet passes through the skew correction unit by pressing the sheet with the pressing unit so that the sheet is separated from the contact part. It is possible to reduce the noise and the deformation of the sheet front end.

FIG. 3 is a diagram illustrating a schematic configuration of a laser beam printer as an example of an image forming apparatus including a sheet conveying device according to a reference example . FIG. 4 is a diagram illustrating a configuration of a skew feeding correction unit provided in the sheet conveying apparatus. The figure explaining the structure of the said skew feeding correction part. It is explanatory drawing which shows the effect of the said skew correction part. FIG. 3 is a diagram illustrating a configuration of a skew feeding correction unit provided in the sheet conveying apparatus according to the first embodiment of the present invention. The figure explaining the operation | movement at the time of skew correction of the said skew correction part. FIG. 6 is a diagram illustrating a configuration of a skew feeding correction unit provided in a sheet conveying apparatus according to a second embodiment of the present invention. It is a perspective view of the conventional skew correction part installation. It is sectional drawing which shows operation | movement of the conventional sheet registration apparatus. It is sectional drawing which shows the subject in the conventional sheet resist apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram illustrating a schematic configuration of a laser beam printer as an example of an image forming apparatus including a sheet conveying device according to a reference example .

  In FIG. 1, reference numeral 100 denotes a laser beam printer main body (hereinafter referred to as a printer main body). The printer main body 100 includes an image forming unit 101, a sheet feeding device 102 that feeds a sheet P, and a sheet conveying device 103 that conveys a sheet fed from the sheet feeding device 102 to the image forming unit 101. ing.

  Here, the image forming unit 101 includes a cartridge unit 5 having a photosensitive drum 6 as an image carrier and a laser scanner 8 for exposing the photosensitive drum 6. In the image formation, the photosensitive drum 6 is exposed by the laser scanner 8 to form a latent image on the surface of the photosensitive drum, and then the latent image is developed to form a toner image on the surface of the photosensitive drum. Try to form.

  The sheet feeding device 102 is configured to receive a sheet feeding cassette 1 that is a sheet stacking unit that is detachably provided in the printer main body 100 and a sheet P that is provided above the sheet feeding cassette 1 and is stored in the sheet feeding cassette 1. A feeding roller 2 for feeding out is provided. Further, the sheet conveying device 103 includes an intermediate conveying roller 3, an intermediate conveying roller 4, a skew correction unit 104, and the like. In FIG. 1, reference numeral 13 denotes an electrical board having a power source and electrical components for driving and controlling the components.

  Next, an image forming operation in the laser beam printer configured as described above will be described. When the image forming operation is started, first, the sheets P stacked and stored in the sheet feeding cassette 1 are sent out by the feeding roller 2. Thereafter, the sheet P is conveyed by the intermediate conveyance roller 3 and the intermediate conveyance roller 4 to the skew correction unit 104 to correct the skew, and then conveyed to the transfer unit including the photosensitive drum 6 and the transfer roller 7. Is done.

  A sheet detection unit (not shown) is provided on the conveyance path from the skew correction unit 104 to the transfer unit. When the leading edge of the sheet P is detected by the sheet detector, a laser beam is emitted from the laser scanner 8 to the photosensitive drum 6 based on image information after a predetermined time from the leading edge detection. An electrostatic latent image is formed on 6. Thereafter, the electrostatic latent image is developed and visualized as a toner image, and the toner image formed on the photosensitive drum is transferred to a predetermined position on the sheet P by the transfer roller 7 at the transfer portion. .

  Next, the sheet P onto which the toner image has been transferred in this manner is conveyed to a fixing device 105 having a fixing roller 9 and a pressure roller 10, and is heated and pressed by the fixing device 105, whereby the toner image is formed. It is fixed. After the image is fixed in this manner, the sheet P is discharged to a discharge unit 106 provided on the upper surface of the printer main body by a pair of discharge rollers 11 and 12.

FIG. 2 is a diagram illustrating a configuration of the skew feeding correction unit 104 according to the present reference example . In FIG. 2, a plurality of registration rollers 54 are first rotating bodies provided in the width direction orthogonal to the sheet conveying direction, and a plurality of 55 are arranged at intervals in the width direction so as to be in contact with and away from the registration rollers 54. This is a resist roller which is a second rotating body. Further, 52 is a registration roller shaft, 53 is a registration roller shaft, and 21 is a plurality of shutter members provided between the registration rollers 55. The shutter member 21 is coaxially aligned with the registration rollers 55. It is supported rotatably.

  Here, by providing a plurality of shutter members 21 as described above, it is possible to deal with sheets having various sheet widths. Further, the shutter member 21 is connected by a connecting member 22, so that the plurality of shutter members 21 are integrally rotated coaxially with the registration roller shaft 53.

Each shutter member 21 has an abutting portion 21a that abuts against the sheet, and the abutting portion 21a is a rotating body constituted by a resist roller 54 and a resist roller 55 until the sheet is conveyed. It is located upstream of the pair of nip portions in the conveying direction. In this reference example , the shutter member 21 is arranged coaxially with respect to the registration roller shaft 53. However, as another configuration, the shutter member 21 may be arranged coaxially with respect to the registration roller shaft 52.

By the way, until the shutter member 21 comes into contact with the sheet, as shown in FIG. 3A, the home position in which the contact portion 21 a is positioned on the upstream side in the conveyance direction of the nip portion between the registration roller 54 and the registration roller 55. Is located. Further, when located in such g e home position, the shutter member 21 by a spring member 57 shown in its own weight and 2 of the shutter member 21 and the connecting member 22, the biasing force F of the sheet conveyance direction and opposite direction It works. For this reason, when the shutter member 21 is at the home position, that is, when the contact portion 21a is in the first posture located on the upstream side in the conveyance direction of the nip portion between the registration roller 54 and the registration roller 55, the sheet and Even if it abuts, the sheet P can be locked.

Further, as shown in (b) of FIG. 3, when the sheet is in contact with the contact portion 21a is conveyed, the contact portion 21a, acts conveying force F _p of the sheet P, after this, the sheet P Is further conveyed, the sheet P will eventually form a loop. Here, when the loop is formed in this manner, the leading edge of the sheet abuts against the abutting portion 21a of the shutter member 21 in the entire width direction of the sheet due to the strength of the sheet itself, and the leading edge of the sheet eventually becomes parallel to the shutter member 21. The skew of the sheet P is corrected.

Then, after the skew is corrected in this manner, in the conveyance force F _p of the contact with the sheet P to the shutter member 21 comes to exceed the biasing force F, the shutter member 21 is pressed by the sheet P Figure The rotation starts in the direction of arrow G. After that, the shutter member 21 moves to a retreat position where the contact portion 21a passes through the nip portion of the registration roller pair 54, 55 and assumes the second posture in which the sheet P can pass.

By the way, when the sheet is a thin sheet, when correcting the skew of the sheet as described above, since the stiffness of the sheet is weak, the leading end may be bent following the contact portion of the shutter member when passing the sheet. . Therefore, in the present reference example , the protruding portion 21b is provided in the vicinity of the upstream side of the contact portion 21a of the shutter member 21 in the shutter member rotation direction. Then, the sheet that has reached the nip portion of the pair of registration rollers 54 and 55 is pressed in the direction away from the contact portion 21a by the protruding portion 21b while rotating the shutter member 21. The protruding portion 21b, which is a pressing portion that presses the sheet in a direction away from the contact portion 21a, is provided to protrude outward from the resist roller 55.

  By providing the protruding portion 21b at such a position, when the leading end of the sheet passes through the nip portion of the pair of registration rollers 54 and 55 while rotating the shutter member 21, the leading end of the protruding portion 21b It comes to press from above. Accordingly, the sheet that has reached the nip portion of the pair of registration rollers 54 and 55 can be moved away from the contact portion 21a while rotating the shutter member 21 by contacting the contact portion 21a. As a result, it is possible to regulate the bending of the sheet tip following the contact portion 21a.

Next, with reference to FIG. 3, the range in which the position of the leading end portion 21 c that restricts the sheet in the protruding portion 21 b indicated by the black circle is provided in the present reference example together with the operation of the shutter member 21.

  When the shutter member 21 is in the first posture (home position), as shown in FIG. 3A, the tip 21c of the protrusion 21b is radially outward from the outer shape of the adjacent registration roller 55. And it is located in the range of the resist roller 55 side across the sheet conveyance path. As shown in FIG. 3 (b), the sheet P is brought into contact with the contact portion 21a, and the projecting portion 21b from the home position until the contact portion 21a passes the nip portion of the registration roller pair 54, 55. The front end portion 21c is located on the resist roller 55 side with the sheet conveyance path interposed therebetween. Further, as shown in FIG. 3C, the leading end 21c of the protruding portion 21b is kept in the sheet conveyance path until the contact portion 21a rotates through a certain range after passing through the nip portion of the registration roller pair 54, 55. Is provided at a position so as to enter the registration roller 54 side.

Thus, in this reference example , the protruding portion 21b is located away from the sheet conveyance path until the leading end of the sheet is nipped by the pair of registration rollers 54 and 55, and does not interfere with the sheet. It is like that. The leading end 21c of the protruding portion 21b enters the sheet conveyance path only after the leading edge of the sheet passes through the nip portion of the registration roller pair 54, 55 and the sheet is nipped by the registration roller pair 54, 55. It is formed with respect to the shutter member 21 at such a position.

  Thereby, before the sheet leading edge is nipped by the pair of registration rollers 54 and 55, that is, when the sheet leading edge is in a free state, the sheet P does not receive a force from the protruding portion 21b. As a result, an extra force is applied to the skew-corrected sheet, or the registration roller pairs 54 and 55 are in a state where the sheet is pushed by the protrusion 21b and locally undulates in the vicinity of the shutter member 21. Can be avoided.

  Here, in the skew feeding correction unit 104 including the shutter member 21 having such a configuration, skew feeding correction is performed in the same manner as the operation of a normal registration shutter until the sheet is nipped between the registration roller pairs 54 and 55. Is called. Next, the sheet P on which the skew correction has been performed is conveyed while rotating the shutter member 21, and eventually the leading end is nipped between the registration roller pairs 54 and 55.

  When the sheet passes through the nip portion, the leading edge of the sheet follows the contact portion 21a by being pressed from above by the protruding portion 21b that has entered the registration roller side from the registration roller side across the sheet conveyance path. The behavior of the shutter member 21 bending in the retracting direction is restricted. As a result, it is possible to reduce the occurrence of splashing noise and edge breakage at the front end of the sheet.

  Next, the protrusion amount of the protrusion 21b with respect to the resist roller 55 and the distance from the contact portion 21a for more effectively preventing the sheet from bending will be described with reference to FIG. In FIG. 4 (a), Q is an experimental member affixed in the vicinity of the contact member 21a of the shutter member 21 on the upstream side in the shutter member rotation direction. The experimental member Q has a protrusion q. It is provided so as to protrude outward from the resist roller 55.

  In this experiment, a horizontal distance (protrusion amount) from the registration roller 55 of the tip qa of the protrusion q of the experimental member Q indicated by a black circle is defined as x, and a vertical distance from the rotation center of the shutter member 21 is defined as y. To do. In this experiment, a sheet in which the contact portion 21a of the shutter member 21 is scratched and the paper tip is caught by the scratch on the contact portion 21a and bent in the rotation direction is used for the experiment. The effect of the protrusion q was verified by whether or not the catch was peeled off by the protrusion q of the member Q. FIG. 4B shows the result when x is fixed at a position of 1.4 mm and y is changed, and FIG. 4C shows the result when x is changed while y is fixed at a position of 4 mm. Show.

  Then, as shown in the results of FIGS. 4B and 4C, by sticking the experimental member Q to the shutter member 21, it is clearly possible to catch the leading edge of the sheet after passing through the nip portion of the registration roller pair. The number of times has decreased, and the effect can be confirmed. Further, from FIG. 4B, it can be seen that the larger y is, that is, the closer the position of the tip qa of the protruding portion q is to the contact portion 21a in the shutter member 21, the more effective.

  In addition to this result, when visually confirming, the larger the y, the earlier the timing at which the sheet is released, and the amount of deflection of the sheet leading edge following the shutter member 21 can be confirmed. It was. Similarly, from FIG. 4C, it can be seen that the larger the x is, that is, the larger the amount of protrusion of the tip qa of the protrusion q from the resist roller 55, the more effective. Therefore, the position of the protruding portion 21b is as close as possible to the contact portion 21a and from the registration roller 55 within the range where the leading end of the sheet does not enter the conveyance path until it is nipped by the pair of registration rollers 54 and 55. It is desirable to provide at a position where the protruding amount is large.

As described above, in this reference example , the sheet that has reached the nip portion of the pair of registration rollers 54 and 55 while pressing the shutter member 21 is pressed in the direction away from the contact portion 21a by the protruding portion 21b. ing. That is, when the sheet reaches the nip portion of the registration roller pair 54 and 55 while pressing the contact portion 21a and rotating the shutter member 21, the sheet protrudes from the contact portion 21a. It is made to press by. As a result, the behavior in which the leading end of the sheet that has passed through the nip portion of the registration roller pairs 54 and 55 follows the contact portion 21a and bends in the retracting direction of the shutter member 21 is regulated. As a result, it is possible to reduce noise and deformation of the sheet leading edge when the sheet passes through the skew feeding correction unit 104.

Furthermore, in this reference example , the sheet is pressed by the protruding portion 21b after the leading end of the sheet reaches the nip portion of the pair of registration rollers 54 and 55. That is, the sheet is prevented from coming into contact with the pair of registration rollers 54 and 55 until reaching the nip portion. As a result, the sheet can be prevented from being pressed by the protruding portion 21b in a free state, and as a result, the front end of the sheet is directed toward the nip portion of the pair of registration rollers 54 and 55 in a stable posture. Can do.

By the way, although the case where the protrusion 21b is formed integrally with the shutter member 21 has been described so far, the protrusion 21b may be provided separately from the shutter member 21. Next, a first embodiment of the present invention in which such a protrusion is provided separately from the shutter member will be described. FIG. 5 is a diagram illustrating a configuration of the skew feeding correction unit 104 provided in the sheet conveying apparatus according to the present embodiment. In FIG. 5, the same reference numerals as those in FIG. 2 described above indicate the same or corresponding parts.

  In FIG. 5, 31 is a shutter member, and 33 is a protruding member that constitutes a pressing portion that presses the sheet that has reached the nip portion of the registration roller pair 54 and 55 in a direction away from the contact portion while rotating the shutter member 31. is there. The projecting member 33 is provided on the shutter member 31 so as to be able to appear and retract in the rotational radius direction of the shutter member 31 indicated by arrows J and J ′.

  Here, as shown in FIGS. 6A and 6B, the protrusion tip 33a of the protrusion member 33 indicated by a black circle in the drawing is aligned with the registration roller until the sheet is nipped between the registration roller pairs 54 and 55. It is arranged on the resist roller 55 side outside the sheet 55 and across the sheet conveyance path.

  When the leading edge of the sheet is nipped by the pair of registration rollers 54 and 55 and the protruding member 33 enters the sheet conveying path, the protruding member 33 is located on the sheet conveying path as shown in FIG. By P, the resist roller 55 is moved to the rotation center side (arrow J direction). At this time, a force acts on the registration roller 54 side due to the weight of the protruding member 33 on the leading edge of the sheet. By the force of the protruding member 33 due to its own weight, bending due to the leading end of the sheet following the contact portion 31a is prevented. Further, since the protruding member 33 is retracted from the sheet conveying path to the registration roller 55 side, the sheet can be conveyed without being deformed by receiving excessive force by the protruding member 33 even after the leading end of the sheet is prevented from being bent. It becomes. After the sheet passes through the shutter member 31, the protruding member 33 returns to the outside of the registration roller 55 by its own weight, and prepares for the conveyance of the next sheet.

Next, a description will be given of a second embodiment of the present invention. FIG. 7 is a diagram illustrating a configuration of the skew feeding correction unit 104 provided in the sheet conveying apparatus according to the present embodiment. In FIG. 7, the same reference numerals as those in FIG. 5 described above indicate the same or corresponding parts.

  In FIG. 7, reference numeral 41 denotes a shutter member, and a protrusion member 43 is provided on the shutter member 41 so as to be able to protrude and retract in the rotational radius direction of the shutter member 41 indicated by arrows J and J ′. In the present embodiment, an urging spring 44 that is an urging member is provided between the shutter member 41 and the protruding member 43, and the urging spring 44 normally causes the protruding member 43 to protrude. The shutter member 41 protrudes outward in the rotational radial direction.

  Then, by causing the protruding member 43 to protrude outward in the rotational radius direction of the shutter member 41 in this way, immediately after the leading end of the sheet is nipped by the registration roller pair 54 and 55, in addition to the weight of the protruding member 43, the biasing means An urging force of 44 acts on the leading edge of the sheet. For this reason, it can prevent more reliably that the sheet | seat front end follows the contact part 41a and bends.

Since also in this embodiment, similarly to the first embodiment described above, the protruding member 43 is retracted from the moves to the center of rotation of the resist roller 55 by the sheet on the conveying path sheet conveying path Deformation is prevented without applying extra force to the sheet.

  Heretofore, the shutter member 21 has been described as having a configuration in which the shutter member 21 is disposed on the pair of registration rollers 54 and 55 on the upstream side in the sheet conveyance direction from the image forming unit. For example, the present invention can be similarly applied to a configuration arranged on a pair of double-sided conveyance rollers in an image forming apparatus having a double-sided printing function. In the past, a plurality of registration rollers 54 arranged at intervals in the width direction orthogonal to the sheet conveying direction have been used as the first rotating body, but a single roller long in the width direction is used as the registration roller 54. Also good.

DESCRIPTION OF SYMBOLS 21 ... Shutter member, 21a ... Contact part, 21b ... Projection part, 21c ... Tip part, 31 ... Shutter member, 33 ... Projection member, 33a ... Projection part tip, 41 ... Shutter member, 43 ... Projection member, 44 ... With Force spring, 53 ... Registration roller shaft, 54 ... Registration roller, 55 ... Registration roller, 57 ... Spring member, 100 ... Laser beam printer main body, 101 ... Image forming unit, 103 ... Sheet conveying device, 104 ... Skewing correction unit, P ... Sheet

Claims (5)

In a sheet conveying apparatus having a skew correction unit that corrects skew of a sheet,
The skew correction unit
A pair of rotating bodies having a plurality of second rotating bodies arranged at intervals in the width direction perpendicular to the first rotating body and the sheet conveying direction;
A sheet that is rotatably provided between the plurality of second rotating bodies, is urged in the direction opposite to the sheet conveying direction, and is directed toward the rotating body pair upstream of the nip portion of the rotating body pair in the sheet conveying direction. A shutter member that corrects the skew by contacting the sheet and rotates while resisting the biasing force that is pressed by the sheet with the skew corrected, and the shutter member enters the nip portion of the pair of rotating bodies, and
The shutter member has a contact portion that is positioned upstream of the nip portion of the rotating body pair in the sheet conveying direction and contacts the sheet toward the rotating body pair until the sheet contacts, and more than the contact portion. located in the dynamic upstream shutter member rotation, the sheet reaches the nip portion of the pair of rotating members while rotating the shutter member to press the contact portion, the sheet as the sheet is separated from the contact portion and a pressing portion for pressing the,
The pressing portion has a protruding position in which a tip protrudes outward from the second rotating body when viewed from the axial direction of the second rotating body, and a retracted position inside the shutter member from the protruding position. A sheet conveying apparatus characterized in that the sheet conveying apparatus is movable .   The sheet conveying apparatus according to claim 1, wherein the pressing portion is provided so as not to contact the sheet until the sheet reaches a nip portion of the pair of rotating bodies. The sheet conveying apparatus according to claim 2 , wherein a biasing member that biases the pressing portion in a protruding direction is provided between the pressing portion and the shutter member. The shutter member, the sheet conveying device according to any one of claims 1 to 3, characterized in that provided rotatably to the second rotating body coaxially. An image forming unit that forms an image on a sheet, and a sheet conveying device according to any one of claims 1 to 4 that conveys the sheet to the image forming unit while correcting skew feeding. An image forming apparatus.

Images