JP2014201387A - Sheet transport device and image formation apparatus with sheet transport device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet transport device that can securely transport a sheet type medium to be recorded and facilitate jam processing for paper jamming, and an image formation apparatus with the same.SOLUTION: The present invention relates to a sheet transport device which holds a sheet type form between a driving roller and a driven roller driven by the driving roller and sends the form in a transport direction, and the sheet transport device includes a shaft which supports the driven roller rotatably, a guide member which displaces the position of the driven roller with respect to the driving roller, and an energization member which presses the driven roller against the driving roller. The shaft includes a cut part, which is so sectioned as to have a first flat part on an upstream side in a form transport direction and an arcuate part connecting with the first flat part. The guide member has a guide hole into which the cut part is inserted to be supported slidably, and a slide surface of the guide hole is inclined toward a downstream side in the transport direction to a virtual line connecting the centers of rotation of the driving roller and driven roller.

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet-like recording medium, and in particular, a sheet conveying apparatus configured to convey a sheet-like recording medium by a driving roller and a driven roller that is in pressure contact with the driving roller. 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 has a built-in sheet conveying device for conveying a sheet, which is a sheet-like recording medium.

  FIG. 7 is a perspective view showing the configuration of the sheet conveying apparatus described in Patent Document 1. As shown in FIG. The sheet conveying apparatus includes a driving roller 100 driven by a driving system, and a driven roller 101 that is pressed against the driving roller 100 and driven by a nip pressure with the driving roller 100.

  The driven roller 101 is in pressure contact with the approximate center of the drive roller 100, and its length substantially matches the lateral width of the paper. The driven roller 101 is a cylindrical body, and a rotation shaft 102 is fitted on the inner peripheral surface thereof. Both ends of the rotating shaft 102 are fitted into a cylindrical bearing 103 and supported rotatably. Each bearing 103 is held by a holding member 104 having an L-shaped cross-section standing on a conveyance base that forms an exterior (not shown).

  FIG. 8 is a schematic side view showing the holding structure of the driven roller 101. A linear portion 105 is provided on the outer peripheral surface of the bearing 103 to prevent the rotating shaft 102 from rotating together. The holding member 104 has a support hole 106 for inserting and supporting the bearing 103. The support hole 106 has a pair of flat surfaces 107 facing the linear portion 105 of the bearing 103. The flat surface 107 of the support hole 106 is longer than the straight portion 105 of the bearing 103, and the bearing 103 is slidably supported along the flat surface 107 in the support hole 106.

  A compression coil spring 109 is compressed and attached as an urging member between the conveying base 108 and the outer peripheral surface of the bearing 103, and the driven roller 101 is pressed against the driving roller 100 by urging the bearing 103. ing. The compression coil spring 109 is arranged so that this direction and the axial direction of the compression coil spring 109 are parallel so that the urging force acts along the direction in which the driven roller 101 and the drive roller 100 are arranged.

JP 2002-46887 A

  However, in the sheet conveying apparatus described in Patent Document 1, when a paper jam occurs between the driving roller 100 and the driven roller 101, there is a problem that it is difficult to remove the paper.

  When the paper P sandwiched between the driving roller 100 and the driven roller 101 is to be pulled out in the transport direction A with the driving roller 100 stopped, the driven roller 101 is pulled up together with the paper P, and the rotating shaft 102 and the bearing The frictional force is increased at the contact surface 110 with the roller 103, and the driven roller 101 cannot be rotated. When the sheet P is further pulled up in this state, the edge 111 of the bearing 103 bites into the support hole 106 of the holding member 104 and cannot slide along the flat surface 107, and resists the surface friction of the driven roller 101 and the driving roller 100. As a result, the sheet P is damaged, and the sheet conveying device needs to be disassembled in order to take out the damaged sheet P.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to be able to reliably transport a sheet-like recording medium and to easily perform jam processing due to a paper jam. An object of the present invention is to provide a sheet conveying apparatus that can be used, and an image forming apparatus including the sheet conveying apparatus.

  A sheet conveying apparatus according to the present invention is a sheet conveying apparatus that sandwiches a sheet-like sheet between a driving roller and a driven roller driven by the driving roller and feeds the sheet in a conveying direction, and rotatably supports the driven roller. A shaft, a guide member that displaces the position of the driven roller with respect to the drive roller, and a biasing member that presses the driven roller against the drive roller, the shaft includes a notch, and the cross-sectional shape of the notch is The guide member has a first flat portion and an arc portion connected to the first flat portion on the upstream side in the sheet conveying direction, and the guide member has a guide hole that is slidably supported through the notch portion. The sliding surface of the hole is provided so as to be inclined toward the downstream side in the transport direction with respect to an imaginary line connecting the rotation centers of the driving roller and the driven roller.

  In the sheet conveying apparatus according to the present invention, the cross-sectional shape of the notch portion includes a second flat portion provided on the downstream side in the conveying direction, and the arc portion includes the first flat portion and the second flat portion. And may be provided on the drive roller side.

  Further, in the sheet conveying apparatus according to the present invention, the connection point between the second flat portion and the arc portion is perpendicular to the sliding direction of the notch portion, and from a virtual axis passing through the midpoint of the first flat portion of the notch portion. It may be located on the side opposite to the drive roller side.

  In the sheet conveying apparatus according to the present invention, the urging member may be installed so that the urging force acts in a direction parallel to the sliding surface of the guide hole.

  An image forming apparatus according to the present invention includes the sheet conveying apparatus according to the present invention.

  The sheet conveying device according to the present invention has an effect of reducing friction between members and easily handling a paper jam generated in the sheet conveying device.

It is a schematic block diagram of the sheet conveying apparatus which concerns on Embodiment 1 of this invention. FIG. 2 is a front cross-sectional view illustrating a holding structure of a driven roller of the sheet conveying device illustrated in FIG. 1. FIG. 3 is a side cross-sectional view illustrating a holding structure of a driven roller of the sheet conveying device illustrated in FIG. 1. It is an enlarged view which shows the detail of the notch part and guide member in FIG. It is an enlarged view which shows the detail of the notch part and guide member of the sheet conveying apparatus which concerns on Embodiment 2 of this invention. FIG. 6 is a schematic side view of an image forming apparatus including a sheet conveying device according to a third embodiment of the present invention. It is a perspective view which shows the structure of the conventional sheet conveying apparatus. FIG. 8 is a cross-sectional view illustrating a driven roller holding structure of the conventional sheet conveying device illustrated in FIG. 7.

  Embodiments of a sheet conveying apparatus and an image forming apparatus including the sheet conveying apparatus according to the present invention will be described below with reference to the drawings. It should be noted that the following embodiment is merely an example in which the present invention is embodied, and it is needless to say that the embodiment can be appropriately changed without departing from the gist of the present invention.

Embodiment 1
FIG. 1 is a schematic configuration diagram of a sheet conveying apparatus according to Embodiment 1 of the present invention.

  The sheet conveying apparatus according to Embodiment 1 of the present invention sandwiches and conveys a sheet P, which is a sheet-like recording medium, by a pair of conveying rollers 3 including a driven roller 1 and a driving roller 2. In the following description, the arrow symbol A in the figure indicates the conveyance direction of the paper P.

  The driving roller 2 has a shaft 4 of the driving roller 2 inserted therein, and the shaft 4 of the driving roller 2 is connected to and supported by driving means (not shown).

  The driven roller 1 is a cylindrical body, and the shaft 5 of the driven roller 1 is fitted therein. The shaft 5 of the driven roller 1 is inserted and supported by a guide member 7 provided on the inner wall 6 of the casing of the sheet conveying apparatus. The driven roller 1 is urged by a compression coil spring 8 provided as a urging member between the inner wall 6 of the housing of the sheet conveying device and the shaft 5 of the driven roller 1 and is pressed against the driving roller 2. .

  Hereinafter, the holding structure of the driven roller 1 will be described in detail with reference to the drawings.

  FIG. 2 is a front cross-sectional view showing the holding structure of the driven roller 1 taken along the broken line I shown in FIG. In FIG. 2, an arrow A indicates the conveyance direction of the paper P.

  As shown in FIG. 2, the driven roller 1 is a cylindrical body, and the shaft 5 of the driven roller 1 is inserted into the inner peripheral surface of the driven roller 1 so as to be rotatably supported. The inner diameter of the driven roller 1 is set larger than the outer diameter of the shaft 5 of the driven roller 1 that is inserted. As shown in FIG. 2, the shaft 5 of the driven roller 1 includes a notch 10 having a D-shaped cross section formed by cutting a part of the shaft 5. As shown in FIG. 2, the shaft 5 of the driven roller 1 is supported by inserting a notch 10 having a D-shaped cross section into the guide hole 11 of the guide member 7.

  Therefore, the shaft 5 of the driven roller 1 is fixed by the notch 10 being inserted through the guide hole 11 and is not rotated by the rotation of the driven roller 1.

  FIG. 3 is a side sectional view showing the holding structure of the driven roller 1 taken along the broken line II shown in FIG. In FIG. 3, the arrow A indicates the transport direction of the paper P as in FIG. In FIG. 3, an arrow B indicates the rotation direction of the driving roller 2, and an arrow C indicates the rotation direction of the driven roller 1 driven and rotated by the driving roller 2.

  Furthermore, a virtual line D shown in FIG. 3 is a virtual line connecting the rotation centers of the driven roller 1 and the driving roller 2 when the driven roller 1 is in a position pressed against the driving roller 2. An arrow E indicates a biasing direction in which the compression coil spring 8 biases the shaft 5 of the driven roller 1.

  As shown in FIG. 3, the guide hole 11 has a substantially rectangular cross-sectional shape, and is provided so that the cutout portion 10 having a D-shaped cross section can slide along the flat surface and the position of the driven roller 1 can be displaced. ing. The longitudinal direction of the guide hole 11 is inclined by a predetermined angle θ on the downstream side in the transport direction A with respect to a virtual line D connecting the rotation centers of the driven roller 1 and the drive roller 2.

  The compression coil spring 8 is erected on the inner wall 6 of the casing of the sheet conveying apparatus so as to urge the shaft 5 of the driven roller 1 parallel to the longitudinal direction of the guide hole 11.

  With the above configuration, the driven roller 1 is supported so that it can rotate without rotating the shaft 5 of the driven roller 1. As shown in FIG. 3, the driven roller 1 is driven by a driving roller 2 that rotates in the direction of arrow B when the paper P is conveyed, and rotates in the direction of arrow C.

  Hereinafter, the structure of the notch 10 and the guide member 7 will be described in detail.

  FIG. 4 is an enlarged view showing details of the notch 10 and the guide member 7 in FIG. 3.

  The cross-sectional shape of the notch 10 has a flat portion 13 on the upstream side in the transport direction A and an arc portion 14 on the downstream side in the transport direction A. Accordingly, the flat portion 13 of the notch 10 faces the flat surface 15 of the guide hole 11 on the downstream side in the transport direction A, and the arc portion 14 of the notch 10 has one point with the flat surface 15 of the guide hole 11 on the downstream side of the transport direction A. It touches with. The flat surface 15 of the guide hole 11 is longer than the flat portion 13 of the notch 10, and the notch 10 is slidably supported along the flat surface 15 of the guide hole 11.

  Hereinafter, an effect when the user tries to pull out the paper P jammed between the driven roller 1 and the driving roller 2 in the conveying direction A in the sheet conveying apparatus having the above-described configuration will be described.

  In order to pull out the paper P jammed between the driving roller 2 and the driven roller 1, the user pulls the paper P against the frictional force that the paper P receives from the driving roller 2 and the driven roller 1 pressed against the driving roller 2. Must be withdrawn.

  Here, in the sheet conveying apparatus according to the first embodiment of the present invention, as shown in FIG. 3, the urging direction E by the compression coil spring 8 is such that the center of the shaft 4 of the driving roller 2 and the center of the shaft 5 of the driven roller 1. Is inclined by a predetermined angle θ on the downstream side in the transport direction A. Therefore, the driven roller 1 is caused to rotate in the direction of the arrow C by the drag in the imaginary line D direction received at the contact point with the driving roller 2 and the biasing force by the compression coil spring 8 even when the driving roller 2 is stopped. Receive. Therefore, when the user tries to pull out the paper P along the transport direction A, the driven roller 1 is easier to rotate than the conventional example.

  As shown in FIG. 4, the notch 10 has an arc portion 14 on the downstream side in the transport direction A. The arc portion 14 of the notch 10 has a guide hole 11 in the rotation direction C in which the driven roller 1 rotates even if the user pulls out the paper P and the shaft 5 of the driven roller 1 is pulled up with the driven roller 1. The flat surface 15 is to be rolled. Therefore, the notch 10 does not bite into the flat surface 15 of the guide hole 11 on the downstream side in the transport direction A, and the sliding of the guide member 7 in the guide hole 11 is not hindered.

  Therefore, the driven roller 1 is easily separated from the driving roller 2, so that the user can take out the paper P jammed between the driven roller 1 and the driving roller 2 more easily than the conventional sheet conveying apparatus.

  Here, since the load due to biting is not generated in the circular arc portion 14 on the downstream side in the transport direction A, the notch portion 10 has a flat portion 13 on the upstream side in the transport direction A when the user tries to pull out the paper P. There is a possibility that a load is generated at the positions of the edges 16a and 16b of the notch 10 at both ends.

  However, the circular arc portion 14 of the notch 10 and the flat surface 15 of the guide hole 11 are in contact with each other only at one point, and the notch 10 and the guide hole 11 have sufficient clearance. The time until the edge 16a of a notch 10 bites into the flat surface 15 of the guide hole 11 is delayed. Therefore, the load caused by the edge 16a of the notch 10 biting in starts to rotate the driven roller 1 with respect to the shaft 5 until the load by which the edge 16a bites into the flat surface 15 increases, so the user pulls out the paper P. It won't interfere. Further, the edge 16b of the notch 10 on the drive roller 1 side moves away from the flat surface 15 of the guide hole 11 when the notch 10 starts to rotate. Therefore, the edge 16b of the notch 10 and the flat surface 15 of the guide hole 11 do not cause a load that prevents the user from pulling out the paper P.

[Embodiment 2]
The sheet conveying apparatus according to the second embodiment of the present invention is different from the configuration of the first embodiment only in the cross-sectional shape of the notch.

  Hereinafter, the structure of the sheet conveying apparatus of Embodiment 2 which concerns on this invention is demonstrated using drawing.

  FIG. 5 is a cross-sectional view of the notch 17 and the guide member 7 in the sheet conveying apparatus according to the second embodiment of the present invention. However, the same or corresponding parts as in FIG.

  The cross-sectional shape of the cutout portion 17 of the sheet conveying apparatus shown in the second embodiment is different from the first embodiment in that the first flat portion 13a is provided on the upstream side in the paper conveying direction A, as in the first embodiment. A circular arc portion 14 and a second flat portion 13b are provided on the downstream side of A. The second flat portion 13b is provided on the inner wall side of the casing of the sheet conveying apparatus, and the arc portion 14 is provided on the drive roller side. The connection point 18 between the second flat portion 13b and the circular arc portion 14 is perpendicular to the sliding direction X of the cutout portion 17 and passes through the midpoint of the first flat portion 13a with respect to the imaginary axis Y. It is provided on the opposite side.

  According to the above configuration, the second flat portion 13b of the notch portion 17 is formed so that the shaft 5 of the driven roller 1 and the notch portion 17 are flat when the guide roller 11 is rotated with the driven roller 1. Slide away from the surface 15. Therefore, the connection point 18 between the second flat portion 13 b and the circular arc portion 14 does not bite into the flat surface 15 of the guide hole 11. Therefore, at the connection point 18, no load is generated when the notch 17 slides along the guide hole 11.

  Further, unlike the first embodiment, the cutout portion 17 is provided with flat portions 13a and 13b on both the upper surface and the lower surface so as to face the flat surface 15 of the guide hole 11, so that the cutout portion 17 extends in the longitudinal direction of the guide hole 11. On the other hand, it can slide stably.

  Here, as described above, the notch 17 has no bite load at the connection point 18 between the second flat portion on the upper surface and the arc portion 14, so that when the user tries to pull out the paper P, There is a possibility that a load is generated at the positions of the edges 16 a and 16 b of the notch 17 at both ends of the first flat portion 13.

  However, as in the first embodiment, there is sufficient clearance between the notch 17 and the guide hole 11, so that the edge 16 a of the notch 17 on the side opposite to the drive roller 1 is cut into the flat surface 15 of the guide hole 11. Time is delayed. For this reason, the load generated by the edge 16a of the notch 17 biting into the driven roller 1 starts to rotate with respect to the shaft 5 until the load of the edge 16a of the notch 17 biting into the flat surface 15 increases. This does not prevent the paper P from being pulled out. Further, the edge 16b of the notch 17 on the drive roller 1 side moves away from the flat surface 15 of the guide hole 11 when the notch 17 starts to rotate. Therefore, the edge 16b of the notch 17 and the flat surface 15 of the guide hole 11 do not cause a load that prevents the user from pulling out the paper P.

[Embodiment 3]
Next, an image forming apparatus according to Embodiment 3 of the present invention will be described.

  FIG. 6 is a side view showing a schematic configuration of the image forming apparatus 20 according to the embodiment of the present invention.

  The image forming apparatus 20 is, for example, a color copying machine or the like that forms multicolor and single color images on a sheet P that is a predetermined recording medium in accordance with image data transmitted from the outside.

  The image forming apparatus 20 includes a sheet feeding unit 21, a sheet conveyance path 22, an image forming unit 23, a fixing unit 24, a paper discharge unit 25, and the like in the apparatus main body.

  The paper feed unit 21 includes a paper feed tray 26, a pickup roller 27, a paper feed roller 28, and the like. When the pickup roller 27 rotates, the uppermost sheet P of the sheets stacked on the sheet feeding tray 26 is sent to the transport roller 3.

  The sheet conveyance path 22 includes an image forming path 22a, a paper discharge / reverse path 22b, a double-sided conveyance path 22c, and various rollers disposed on these paths. In the image forming path 22a, a conveying roller 3, a registration roller 29, a secondary transfer roller 30, a fixing unit 24, and the like are provided.

  The paper P taken out by the paper feed roller 28 passes through the transport roller 3 positioned downstream thereof, and is temporarily waited at a position of the registration roller 29, and then to the secondary transfer roller 30 by the registration roller 29 in accordance with the timing of image formation. It is conveyed.

  The image is transferred by the image forming unit 23 to the paper P conveyed to the secondary transfer roller 30. The image forming unit 23 includes an image forming unit 31a for yellow, an image forming unit 31b for magenta, an image forming unit 31c for cyan, an image forming unit 31d for black, and an intermediate transfer belt 32. The secondary transfer roller 30 is provided. For example, the image forming unit 31 includes a photosensitive drum 33, a charging device (not shown) arranged around the photosensitive drum 33, an exposure device, a developing device, a primary transfer roller, and a cleaning device.

  The toner images formed on the photoconductive drums 33 of the image forming units 31a, 31b, 31c, 31c, 31d, 31d, 31d, 31d, and 31d are primarily transferred in sequence onto the intermediate transfer belt 32, and a full color image is formed on the intermediate transfer belt 32. A toner image is formed. When the paper P passes between the intermediate transfer belt 32 and the secondary transfer roller 30, the toner image on the intermediate transfer belt 32 is transferred to one side of the paper P.

  The sheet P on which the image is transferred is then conveyed to the fixing unit 24. The fixing unit 24 includes, for example, a heat fixing roller 34 having a heat source and a pressure roller 35 in contact with the heat fixing roller 34, and heats and presses the paper P on which a toner image passing between both rollers is formed. Then, the toner image transferred onto the paper P is fixed on the paper P. The sheet P that has been subjected to the fixing process is conveyed to the paper discharge reverse path 22b.

  A paper discharge roller 36 and a reverse roller 37 are provided in the paper discharge / reverse path 22b. In the case of single-sided printing, the paper P that has passed through the image forming path 22a is guided to the paper discharge / reverse path 22b, and is discharged to the paper discharge unit 25 by the paper discharge roller 36 rotating in the forward direction. On the other hand, in the case of duplex printing, the single-side printed paper P that has passed through the image forming path 22a is guided to the reverse roller 37 side by the switching claw 38, and the reverse roller 37 rotates in the reverse direction after the forward rotation. Then, the trailing edge of the paper becomes the leading edge and is guided to the duplex conveyance path 22c.

  The paper P guided to the double-sided conveyance path 22c is conveyed by the conveyance rollers 3 provided at a plurality of locations along the double-sided conveyance path 22c, and is again guided to the image forming path 22a.

  The sheet conveying apparatus described in the first and second embodiments may be provided anywhere on the various conveying rollers 3 and the secondary transfer roller 30, the registration roller 29, the paper discharge roller 36, and the reverse roller 37 provided in the conveyance path. .

  An open / close cover 39 is provided outside the apparatus where the conveyance path is located. When the opening / closing cover 39 is opened, the above-described transport path is exposed. By opening the opening / closing cover 39, the user can remove the paper P that has caused a paper jam in the sheet conveying path 22.

DESCRIPTION OF SYMBOLS 1 Driven roller 2 Drive roller 3 Conveying roller 4 Drive roller shaft 5 Driven roller shaft 6 Inner wall of housing of sheet conveying device 7 Guide member 8 Compression coil spring 10 Notch portion 11 Guide hole 13 Flat portion of notch portion 14 Notch portion Arc part 15 Flat surface of guide hole 16 Edge of notch part 17 Notch part 18 Connection point 20 Image forming apparatus 21 Paper feed part 22 Sheet transport path 23 Image forming part 24 Fixing part 25 Paper discharge part 26 Paper feed tray 27 Pickup roller 28 Paper feeding roller 29 Registration roller 30 Secondary transfer roller 31 Image forming unit 32 Intermediate transfer belt 33 Photosensitive drum 34 Heating and fixing roller 35 Pressure roller 36 Paper discharge roller 37 Reverse roller 38 Switching claw 39 Opening / closing cover 100 Driving roller 101 Follower roller 103 Bearing 104 Holding member 105 Support hole 1 06 Linear portion of bearing 107 Flat surface of support hole 108 Conveying base 109 Compression coil spring 110 Contact surface of bearing and rotating shaft of driven roller 111 Edge of bearing

Claims (5)

A sheet conveying device that sandwiches a sheet of paper between a driving roller and a driven roller that is driven by the driving roller and sends the sheet in a conveying direction,
A shaft that rotatably supports the driven roller;
A guide member for displacing the position of the driven roller with respect to the driving roller;
An urging member that presses the driven roller against the driving roller,
The shaft includes a notch;
The cross-sectional shape of the notch has a first flat part on the upstream side in the paper transport direction and an arc part connected to the first flat part,
The guide member has a guide hole that is slidably supported through the notch,
The sheet conveying apparatus, wherein the sliding surface of the guide hole is provided to be inclined downstream in the conveying direction with respect to an imaginary line connecting the rotation centers of the driving roller and the driven roller. The cross-sectional shape of the notch has a second flat portion provided on the downstream side in the transport direction,
The sheet conveying device according to claim 2, wherein the arc portion is provided between the first flat portion and the second flat portion and is provided on the drive roller side.   The connection point between the second flat portion and the arc portion is orthogonal to the sliding direction of the notch, and from the virtual axis passing through the midpoint of the first flat portion of the notch to the side opposite to the drive roller side The sheet conveying apparatus according to claim 2, wherein the sheet conveying apparatus is positioned.   The sheet conveying apparatus according to claim 1, wherein the urging member is installed so that an urging force acts in a direction parallel to a sliding surface of the guide hole.   An image forming apparatus comprising the sheet conveying device according to claim 1.