JP2019059560A - Sheet conveying apparatus, image forming apparatus, and image reading apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: In the configuration in which the sheet is reversed by moving the rear end of the sheet to the second holding portion by its own weight after completely discharging the sheet from the first holding portion, there is a possibility that the sheet transportability may be deteriorated. . SOLUTION: A discharge reversing means 6 comprises a drive roller 62, a discharge roller 61 forming a first sandwiching portion N1 with the drive roller 62, and a transport roller 63 forming a second sandwiching portion N2 with the drive roller 62. Have. When the drive roller 62 is moved to switch the conveyance direction of the sheet S, the movement of the drive roller 62 is stopped in a state in which the sheet S conveyed in the first direction is nipped by the plurality of nipping portions. Transport in the direction of 1. [Selected figure] Figure 8

Description

  The present invention relates to a sheet conveying apparatus which conveys a sheet continuously, a copier including the sheet conveying apparatus, an image forming apparatus such as a printer and a facsimile, and an image reading apparatus.

  In recent years, further resource saving is desired for the image forming apparatus, and utilization of double-sided printing is widely used for sheets such as paper, OHP sheet, plastic sheet, and cloth. Therefore, in an image forming apparatus having a double-sided printing function, it is regarded as important to improve the output number of double-sided printing per unit time, that is, double-sided productivity.

  As a prior art, Patent Document 1 discloses a reversing unit having a driving roller, a first driven roller, and a second driven roller, which rotates in one direction in response to a driving force in a reversing unit that reverses a sheet. A configuration in which a roller group is provided is disclosed. In the configuration of the reversing roller group, the three rollers are arranged to be substantially aligned in the order of the first driven roller, the driving roller, and the second driven roller in the direction intersecting the sheet conveying direction. . The first driven roller faces the drive roller to form a first sandwiching portion, and the second driven roller faces the drive roller from a direction different from the first driven roller to form a second sandwiching portion.

  In the reversing unit of Patent Document 1, the sheet is reversed as follows. First, the sheet on which the image is formed on the first surface is conveyed toward the first sandwiching portion of the reversing roller group. Thereafter, the sheet is conveyed in a first direction which is a direction in which the sheet is discharged from the reversing roller group in the first holding unit, and the rear end of the sheet in the sheet conveying direction passes the first holding unit. In the reversing unit, a switchback unit for temporarily storing the sheet is provided downstream of the first holding unit in the sheet conveyance direction, and the sheet having passed through the first holding unit is stored in the switchback unit. Thereafter, the sheet temporarily stored in the switchback portion falls under its own weight, and the rear end of the sheet is guided to the second holding portion of the reversing roller group. Since the drive roller rotates only in one direction, the sheet nipped by the second nipping portion is transported in a second direction opposite to the first direction which is the transport direction in the first nipping portion. Be done. Thereafter, the sheet is conveyed again to the image forming unit, and after an image is formed on the second surface of the sheet, the sheet is conveyed to a sheet discharge unit provided at a position different from the reversing unit. Then, the sheet is discharged from the inside of the image forming apparatus by the sheet discharge roller of the sheet discharge unit.

Unexamined-Japanese-Patent No. 2015-083353

  However, in the configuration of Patent Document 1, after the sheet is completely discharged from the first nipping portion of the reversing roller group to the switchback portion, the rear end of the sheet is moved to the second nipping portion by its own weight to reverse the sheet. Therefore, the following problems occur. That is, in the case where the rear end of the sheet is not reliably nipped by the second nipping portion depending on the thickness of the sheet, the difference in basis weight of the sheet, and the presence or absence of the bending (curling) of the sheet, the sheet transportability is improved. It may decrease.

  Therefore, an object of the present invention is to provide a sheet conveying apparatus capable of suppressing a decrease in sheet conveyance performance.

  The present invention relates to a first rotating body that rotates only in one direction, and a second rotating body that transports a sheet in a first direction together with the first rotating body by rotating the first rotating body. A third rotating body for conveying the sheet together with the first rotating body in a second direction different from the first direction by rotating the first rotating body; and the first rotation By moving the first rotating body while transporting the sheet in the first direction by the body and the second rotating body, the second rotating body contacts the first surface of the sheet and the first rotating body is moved. The first rotation body contacts the second surface of the sheet from the first state in which the first rotation body contacts the second surface opposite to the first surface of the sheet, and the second rotation A third body in contact with the first surface of the sheet and the third rotor in contact with the second surface of the sheet Switching means for switching to a second state in which the first rotating body contacts the first surface of the sheet and the third rotating body contacts the second surface of the sheet after switching to the state; And a stopping means for stopping the movement of the first rotating body to convey the rear end of the sheet in the first direction in the first direction by the rotation of the first rotating body in the third state. , And.

  According to the present invention, it is possible to switch the nipping portion for nipping the sheet before the sheet is completely discharged from the second nipping portion, and thereby, it is possible to suppress the decrease in the transportability of the sheet. A sheet conveying apparatus can be provided.

FIG. 1 is a schematic cross-sectional view illustrating an entire configuration of an image forming apparatus in Embodiment 1. FIG. 6 is a schematic cross-sectional view for explaining the sheet discharge reversing means in the first embodiment. FIG. 6 is a schematic view for explaining the configuration of a discharge reversing unit in the first embodiment. FIG. 7 is a schematic view illustrating the configuration of a rotating body in the discharged paper reversing means of the first embodiment. FIG. 2 is a block diagram in Example 1; (A)-(d) is a schematic diagram explaining the structure of the paper discharge inversion means in Example 1, and operation | movement of a drive roller. (A)-(d) is a schematic sectional drawing explaining the sheet conveyance operation | movement at the time of double-sided printing in Example 1. FIG. (A)-(f) is a schematic diagram explaining operation | movement of a movement of the drive roller in Example 1. FIG. FIG. 8 is a schematic view for explaining the configuration of a discharge reversing unit in the second embodiment. (A)-(f) is a schematic diagram explaining operation | movement of a movement of the drive roller in Example 2. FIG. FIG. 14 is a schematic view illustrating a discharge inverting unit as another configuration of the second embodiment. (A)-(f) is a schematic diagram explaining operation | movement of the movement of the drive roller in the paper discharge inversion means as a modification 1 of Example 2. FIG. (A)-(f) is a schematic diagram explaining operation | movement of the movement of the drive roller in the paper discharge inversion means as a modification 2 of Example 2. FIG. (A)-(g) is a schematic diagram explaining operation | movement of the movement of the drive roller in the paper discharge inversion means of Example 3. FIG. (A)-(e) is a schematic diagram explaining the structure of the paper discharge inversion means in Example 3, and operation | movement of a drive roller. FIG. 18 is a schematic view illustrating the configuration of the stopping means in the fourth embodiment. (A)-(b) is a schematic diagram explaining the structure of a stop means in Example 5. FIG. (A)-(d) is a schematic diagram explaining the operation | movement of a paper discharge inversion means in Example 5. FIG. It is a schematic diagram explaining the other structure of a stop means. FIG. 14 is a schematic cross-sectional view for explaining a sheet conveying apparatus in another embodiment.

  Hereinafter, preferred embodiments of the present invention will be exemplarily described in detail with reference to the drawings. In the following embodiments, an example using a laser beam printer provided with the sheet conveying apparatus of the present invention will be described. However, the components described in this embodiment are merely examples, and the scope of the present invention is not limited to them.

Example 1
FIG. 1 is a schematic cross-sectional view showing the configuration of an image forming apparatus 1 provided with the sheet conveying apparatus of the present invention. As shown in FIG. 1, the image forming apparatus 1 includes a main body 2 of the image forming apparatus 1, a feeding unit 3, an image forming unit 4, a conveyance unit 5, a discharge reversing unit 6, and a conveyance control unit 7. And.

  The main body 2 accommodates the feeding unit 3, the image forming unit 4, the conveyance unit 5, the sheet discharge reversing means 6, and the conveyance control unit 7. The sheet feeding cassette 21 as the containing portion is detachably provided on the upstream side of the feeding portion 3 in the sheet conveying direction, and feeds the unprinted sheets S stored in a stacked state to the feeding portion 3 Do. A sheet discharge tray 22 as a stacking unit for stacking the sheets discharged from the main body 2 after printing is completed is provided on the downstream side of the sheet discharge reversing means 6 in the sheet conveyance direction.

  The feeding unit 3 includes a feeding roller 30, and a separation unit 31 formed of a separation pad 31a and a separation holder 31b for holding the separation pad 31a. The separation pad 31a is in pressure contact with the feeding roller 30, and the sheet S accommodated in the sheet feeding cassette 21 is fed to the separating unit 31 by the rotation of the feeding roller 30, and separated one by one in the separating unit 31. Then, the sheet is fed to the first transport path 50.

  The image forming unit 4 includes a photosensitive drum 40 as an image carrier, a laser scanner unit 41, a developing unit 42, a transfer roller 43, and a fixing unit 44. An electrostatic latent image is formed on the surface of the photosensitive drum 40 by irradiating the photosensitive drum 40 uniformly charged by a charging device (not shown) with the laser scanner unit 41 based on image information. By developing the electrostatic latent image in the developing unit 42, a toner image is formed on the surface of the photosensitive drum 40. The developed toner image is transferred onto the sheet S by the transfer roller 43, and is fixed on the sheet S by being heated and pressed in the fixing unit 44. Thus, an image is formed on the sheet S in the image forming unit 4.

FIG. 2 is a schematic cross-sectional view showing the configuration of the sheet discharge reversing means 6 of the present embodiment. Hereinafter, the configuration of the sheet discharge reversing means 6 will be described with reference to FIG. The sheet discharge reversing means 6 receives the drive force from the drive source and rotates only in one direction (the direction of the arrow R1 in the figure) the drive roller 62 (first rotating body) and the sheet discharge following the rotation of the drive roller 62 A discharge roller 61 having a roller 61 (second rotating body) and a reversing roller 63 (third rotating body) is in contact with the driving roller 62 to form a first sandwiching portion N1, and the first sandwiching portion At N <b> 1, the sheet discharge roller 61 holds the sheet S together with the drive roller 62 and conveys the sheet S. Further, the reversing roller 63 contacts the driving roller 62 at a position different from the discharge roller 61 in the circumferential direction of the driving roller 62 to form a second pinching portion N2, and pinches the sheet S together with the driving roller 62. Transport.

  As the drive roller 62 rotates, the sheet S is conveyed from the drive roller 62 toward the sheet discharge tray 22 by the drive roller 62 and the sheet discharge roller 61, and is discharged from the first sandwiching portion N1. Here, the direction in which the sheet is discharged from the first sandwiching portion N1 toward the sheet discharge tray 22 is taken as a discharge direction (first direction). Further, since the drive roller 62 rotates in only one direction by receiving the drive force, the sheet S is conveyed from the paper discharge tray 22 toward the second conveyance path 51 in the second holding unit N2, The sheet is conveyed in a second direction which is a direction different from the conveyance direction in the sandwiching portion N1. Here, the direction in which the sheet S conveyed in the discharge direction toward the paper discharge tray 22 is conveyed from the paper discharge tray 22 toward the paper discharge reversing means 6 is taken as a reverse direction (second direction).

  That is, when the drive roller 62 rotates only in one direction (in the direction of the arrow R1 in the figure), the sheet S is conveyed in the first direction in the first holding unit N1, and the sheet S in the second holding unit N2 is the first. In the second direction, which is the direction opposite to the direction of. Further, when the sheet discharge reversing means 6 moves the sheet discharge roller 61, the sheet S is switched from being held by the first holding portion N1 to being held by the second holding portion N2. The moving operation of the sheet discharge roller 61 that switches the nipping state of the sheet S will be described in detail later.

  As shown in FIG. 1, the conveyance unit 5 includes a first conveyance path 50, a second conveyance path 51, a conveyance roller pair 52, a re-conveyance roller pair 53, a first sensor 54, and a second sensor. And 55.

  The first conveyance path 50 forms an image on the sheet S in order to form an image again on the sheet S fed from the sheet feeding cassette 21 and the sheet S conveyed in the reverse direction by the sheet discharge reversing means 6. 4 is a conveyance path to be conveyed to 4. Regarding the conveyance direction of the sheet S, the downstream side of the first conveyance path 50 is connected to the first sandwiching portion N1 of the sheet discharge reversing means 6, and the upstream side of the first conveyance path 50 is bifurcated. One side of the bifurcated first conveyance path 50 is connected to the sheet feeding cassette 21, the sheet S is fed from the sheet feeding cassette 21 to the first conveyance path 50, and the transfer roller is formed in the image forming unit 4. The toner image is transferred to the sheet S by 43. Further, the other side of the bifurcated first conveyance path 50 is connected to the second conveyance path 51. The second conveyance path 51 is a conveyance path for re-conveying the sheet S conveyed in the reverse direction by the sheet discharge reversing means 6 to the first conveyance path 50. With respect to the sheet conveyance direction, the upstream side of the second conveyance path 51 is connected to the second holding portion N2 of the sheet discharge reversing means 6, and the downstream side of the second conveyance path 51 is bifurcated first conveyance It is connected to the other side of the path 50.

  The conveyance roller pair 52 is disposed in the first conveyance path 50, and conveys the sheet S fed or conveyed to the first conveyance path 50 along the first conveyance path 50. The re-conveying roller pair 53 is disposed in the second conveyance path 51, and conveys the sheet S conveyed to the second conveyance path 51 to the first conveyance path 50.

  The first sensor 54 is disposed between the feeding unit 3 and the image forming unit 4 in the first conveyance path 50, and detects the position of the front end and the rear end of the sheet S passing through the first sensor. The second sensor 55 is disposed on the downstream side of the first conveyance path 50 in the sheet conveyance direction, and, like the first sensor 54, the positions of the front end and the rear end of the sheet S passing through the second sensor 55 To detect.

  The conveyance control unit 7 controls the drive related to conveyance of the sheet S, such as the feeding roller 30, the pair of conveying rollers 52, the pair of re-conveying rollers 53, and the discharge reversing unit 6, and Control movement related movement. The control of the operation of the discharge reversing means 6 in the conveyance control unit 7 will be described in detail later.

  Next, the configuration of the sheet discharge reversing means 6 in the present embodiment will be described using FIGS. 3 to 5. FIG. 3 is a schematic view showing the configuration of the sheet discharge reversing means 6 in the present embodiment when viewed from the downstream side in the sheet conveyance direction. FIG. 4 is a schematic view showing the configuration of the sheet discharge roller 61, the drive roller 62, and the reverse roller 63 in the present embodiment. FIG. 5 is a block diagram showing the relationship between the conveyance control unit 7, the drive source, and the switching member in the present embodiment.

  As shown in FIG. 3, in the sheet discharge reversing means 6, the drive roller 62 is rotatably held at both ends of the drive roller 62 by a drive roller holder 65 that can rotate around a fulcrum 66. The drive roller holder 65 holds the drive roller 62 at one end side, and a cam contact portion 65 c that contacts the cam 67 is provided at the other end side via the fulcrum 66. A cam 67 rotatable integrally with the cam shaft 68 is provided at each end of the cam shaft 68 provided substantially in parallel to the drive roller 62. Further, a cam drive portion 69 formed of a solenoid 69a (switching member) and a tooth missing gear 69b capable of switching ON / OFF of a drive for rotating the cam 67 is provided on one end side of the cam shaft 68. It is done.

  The sheet discharge reversing guide 64 is supported by both ends of the drive roller 62 in the axial direction, and one end 64 a of the sheet discharge reversing guide 64 on the drive roller 62 side is rotatably held by the bearing 65 b of the drive roller holder 65. ing. In addition, a cylindrical protrusion 64 b is provided at the other end of the discharge reversing guide 64, and the protrusion 64 b is fitted in the groove 72 provided in the main body 2 to obtain the discharge reversing guide 64. The attitude is maintained.

  As shown in FIG. 4, the sheet discharge roller 61 is in contact with the drive roller 62 to form a first sandwiching portion N1, and is held by a sheet discharge roller holder 71 movable around a fulcrum 71a. The sheet discharge roller holder 71 is urged against the drive roller 62 by a spring 81 (first urging member) provided in the main body 2, and the drive roller 62 is pressed by the sheet discharge roller 61. (1) Form the sandwiching portion N1.

  The reversing roller 63 is in contact with the driving roller 62 to form a second sandwiching portion N2, and is held by a reversing roller holder 73 movable around a fulcrum 73a. The reverse roller holder 73 is biased against the drive roller 62 by a spring 83 (second biasing member) provided on the main body 2, and the drive roller 62 is pressed by the reverse roller 63 in a second pinching manner. Form part N2.

  Next, a block diagram for performing drive control in the present embodiment will be described based on FIG. One end side of the drive roller 62 is connected to the gear 70, and receives a drive force from a drive motor 90 as a drive source via the gear 70 to rotate. The drive motor 90 rotates only in one direction, and the drive roller 62 also rotates only in one direction. As shown in FIG. 4, the CPU 110 is connected to the drive motor 90, the solenoid 69 a, the feeding roller 30, the first sensor 54, and the second sensor 55. Further, the CPU 110 is connected to the ROM and the RAM, and executes the program stored in the ROM by using the RAM as a work memory. In the present embodiment, the CPU 110, the ROM, and the RAM constitute the transport control unit 7. Further, in the present embodiment, the conveyance control unit 7 controls the drive motor 90 and the solenoid 69 a so that the rotation of the drive roller 62 and the movement of the drive roller 62 by the cam drive unit 69 in the sheet discharge reversing means 6. The action is taken.

  Here, the movement operation of the drive roller 62 in the sheet discharge reversing means 6 will be described with reference to FIGS. 6 (a) to 6 (d).

  FIG. 6A is a schematic view of the sheet discharge reversing means 6 before the operation of moving the drive roller 62 is viewed from the axial direction of the drive roller 62. FIG. The position of the drive roller 62 at this time is the initial position (first position), and the drive roller 62 rotates in only one direction in response to the driving force from the driving source at the initial position.

  In the state of FIG. 6A, when the solenoid 69a is energized to release the lock of the tooth missing gear 69b, the cam 67 rotates in the direction of the arrow A (clockwise). At this time, the cam contact portion 65c of the drive roller holder 65 is in contact with the cam 67 by being urged by a spring (not shown), and the drive roller holder 65 is centered on the fulcrum 66 by the rotation of the cam 67. It rotates in the direction of arrow B (counterclockwise). Along with this, the drive roller 62 held at its both ends by the drive roller holder 65 moves in a direction away from the sheet discharge roller 61 and the reverse roller 63 (in the direction of the arrow B).

  The sheet discharge reversing guide 64 is supported by both ends of the drive roller 62, and the one end portion 64 a is held by the drive roller holder 65, so the sheet discharge reverse guide 64 moves together with the drive roller 62. Further, since the projection 64 b of the sheet discharge inversion guide 64 is fitted in the groove 72, the sheet discharge inversion guide 64 moves along the groove 72 while changing the angle with the drive roller holder 65. At this time, the gear 70 connected to one end side of the drive roller 62 also moves together with the drive roller 62, and the drive roller 62 rotates in one direction receiving the drive force from the drive motor 90 as a drive source even during movement. Do.

  FIG. 6B is a schematic view of the sheet discharge reversing means 6 in a state in which the drive roller 62 and the sheet discharge reversing guide 64 are moved by the rotation of the cam 67 as viewed from the axial direction of the drive roller 62. 6C is a schematic view of the sheet discharge reversing means 6 when the moving amount of the drive roller 62 is maximized by the rotation of the cam 67 as viewed from the axial direction of the drive roller 62. At this time, the drive roller 62 is located at the retracted position (second position) retracted from the initial position.

  As shown in FIG. 6C, the cam contact portion 65c of the drive roller holder 65 is in contact with an angle D portion having the same maximum diameter and the same diameter of the cam 67. In this contact state, even if the cam 67 continues rotating, the movement of the drive roller 62 can be stopped at a position where the movement amount of the drive roller 62 is maximum. Further, the movement stop time of the drive roller 62 can be set by the rotational speed of the cam 67 and the D portion angle. In the present embodiment, the movement of the drive roller 62 can be stopped for a certain period of time by the stopping means formed by the drive roller holder 65 having the cam contact portion 65 c and the cam 67.

  Further, the discharge roller 61 held by the discharge roller holder 71 is biased against the drive roller 62 by a spring 81 provided in the main body 2. As the drive roller 62 moves, the sheet discharge roller holder 71 rotates around the fulcrum 71 a, and the sheet discharge roller 61 moves toward the reverse roller 63.

  Further, the reverse roller 63 held by the reverse roller holder 73 is biased against the drive roller 62 by a spring 83 provided on the main body 2. As the drive roller 62 moves, the reverse roller holder 73 rotates around the fulcrum 73 a, and the reverse roller 63 moves toward the sheet discharge roller 61.

  At this time, the rotation angle of the sheet discharge roller holder 71 is restricted by the unshown restricting member to the position of FIG. 6C, and the reverse roller 63 is stopped at the position of FIG. It moves to a position in contact with the paper roller 61. As a result, the reverse roller 63 and the sheet discharge roller 61 are in contact with each other, and a third pinching portion N3 capable of pinching and holding the conveyed sheet S is formed.

  Thereafter, as shown in FIG. 6D, when the cam 67 further rotates in the direction of arrow A (clockwise), the drive roller holder 65 rotates about the fulcrum 66 in the direction of arrow C (clockwise). As a result, the drive roller 62 approaches the sheet discharge roller 61 and the reverse roller 63 and moves from the retracted position to the initial position. When the cam 67 returns to the position shown in FIG. 6A, the drive is released by the tooth missing gear 69b, and the rotation of the cam 67 is stopped. At this time, since the solenoid 69a has already been de-energized, the cam 67 is locked at the position where the drive is released. That is, a series of operations in which the drive roller 62 moves in the sheet discharge reversing means 6 is a continuous operation which occurs during one rotation of the cam 67 by the cam drive unit.

  In addition, since the drive roller 62 moves with the gear 70, the drive roller 62 moves through the gear 70 during a series of operations in which the drive roller 62 moves relative to the discharge roller 61 and the reverse roller 63. Keeps rotating in one direction by receiving the driving force from

  FIG. 7A is a schematic cross-sectional view showing a state in which the sheet S stored in the sheet feeding cassette 21 is fed by the feeding roller 30. FIG. As shown in FIG. 7A, the sheet S taken out of the sheet feeding cassette 21 by the feeding roller 30 is separated into one sheet by the separating section 31 and then fed to the first conveyance path 50 and conveyed. The sheet is conveyed to the image forming unit 4 by the roller pair 52. Thereafter, the leading edge of the sheet S is detected by the first sensor 54, and an image is formed on the first surface of the sheet S in the image forming unit 4 at the timing based on the detection information.

  FIG. 7B is a schematic cross-sectional view showing a state immediately before the operation of moving the drive roller 62 is started, with the sheet S on which the image is formed on the first surface is conveyed to the sheet discharge reversing means 6. The sheet S on which the toner image has been transferred to the first surface is nipped by a first nipping portion N1 formed by the drive roller 62 and the sheet discharge roller 61 after the toner image is fixed in the fixing portion 44. The sheet is transported in the direction of the solid line arrow (first direction). At this time, the sheet S is conveyed in the first direction with the first surface in contact with the sheet discharge roller 61 and the second surface in contact with the drive roller 62 (first state).

  The rear end of the sheet S in contact with the drive roller 62 and the discharge roller 61 at the first holding portion N1 is detected by the second sensor 55, and based on the detection information, the rear end of the sheet S of the drive roller 62 is The movement is started before leaving the drive roller 62. That is, in the present embodiment, the sheet discharge roller 61 starts moving before the rear end of the sheet S completely leaves the first holding portion N1. Due to the movement of the drive roller 62, the sheet S nipped by the first nipping portion N1 and conveyed in the first direction is nipped by the second nipping portion N2. The movement of the drive roller 62 is started by the conveyance control unit 7 controlling the solenoid 69 a based on the detection information from the second sensor 55. The movement of the drive roller 62 may be controlled based on detection information of the leading edge of the sheet S by the second sensor 55. Regarding the movement operation of the drive roller 62 at the time of switching from the state in which the sheet S is held by the first holding portion N1 to the state in which it is held by the second holding portion N2, FIGS. Will be described in detail later.

  FIG. 7C is a schematic cross-sectional view showing a state in which the sheet S is nipped by the second nipping portion N2 after the movement operation of the drive roller 62. When the sheet S is nipped from the first nipping portion N1 to the second nipping portion N2 by the movement of the drive roller 62, the sheet S is drawn in the arrow direction indicated by the solid line arrow different from the first direction in the second nipping portion N2. Direction). At this time, the sheet S is conveyed in the second direction with the second surface in contact with the reverse roller 63 and the first surface in contact with the drive roller 62 (second state). Thus, the sheet S conveyed in the first direction in the first holding unit N1 is conveyed in the second direction in the second holding unit N2, and is conveyed to the second conveyance path 51.

  FIG. 7D is a schematic cross-sectional view showing a state immediately before the sheet S conveyed in the second direction is re-conveyed to the image forming unit 4. As shown in FIG. 10, the sheet S conveyed to the second conveyance path 51 is conveyed to the first conveyance path 50 by the re-conveyance roller pair 53. Thereafter, in the image forming unit 4, the toner image is transferred to the second surface by the transfer roller 43 in the image forming unit 4, and fixing of the toner image formed on the second surface is performed in the fixing unit 44. Images are formed on both the surface and the second surface. The sheet S on which the image formation has been completed on both sides is conveyed to the sheet discharge reversing means 6, and is again conveyed in the first direction in the first holding portion N1, and this time the sheet discharge tray is moved without moving the drive roller 62. It is discharged to 22. Thus, double-sided printing of the sheet S in the present embodiment is completed.

  As described above, in the present embodiment, the sheet S is moved by moving the drive roller 62 by the switching means provided with the drive roller holder 65, the cam 67, the cam shaft 68, and the cam drive portion 69. The clamping state is switched from the first state to the second state.

  Here, the movement operation of the drive roller 62 at the time of switching from the state in which the sheet S is nipped by the first nipping portion N1 to the state in which the sheet S is nipped by the second nipping portion N2 It demonstrates using 8 (a)-(f).

  FIG. 8A is a schematic view showing a state immediately before the operation of moving the drive roller 62 is started when the sheet S on which the image is formed on the first surface is conveyed to the first sandwiching portion N1. At this time, the drive roller 62 is rotating in one direction at the initial position (first position). As shown in FIG. 8A, the rear end Re of the sheet S in the present embodiment is the most rear end portion of the sheet S in the first direction in which the sheet S is conveyed.

  FIG. 8B is a schematic view showing a state where the drive roller 62 has started to move from the initial position (first position). As shown in FIG. 8B, the drive roller 62 is a discharge roller before the sheet S contacts the drive roller 62 and the discharge roller 61 and the rear end Re of the sheet S is conveyed by the first sandwiching portion N1. 61 and movement in a direction away from the reverse roller 63 is started.

  FIG. 8C is a schematic view showing a state in which the drive roller 62 moves to the retracted position where the movement amount of the drive roller 62 is maximum, and the movement of the drive roller 62 is stopped for a predetermined time. In the state shown in FIG. 8C, the drive roller 62 is in contact with the sheet discharge roller 61 in a state in which the movement is stopped for a certain period of time to form the first sandwiching portion N1. Further, the reverse roller 63 biased by the spring 83 and the discharge roller 61 biased by the spring 81 with respect to the drive roller 62 abut through the sheet S as the drive roller 62 moves, 3 Forming a sandwiching portion N3.

  At this time, the first sandwiching portion N1 and the third sandwiching portion are in a state (third state) in which the sheet S has the first surface in contact with the sheet discharge roller 61 and the second surface in contact with the drive roller 62 and the reverse roller 63. It is nipped by N3 and conveyed in the first direction. That is, when the drive roller 62 is moved from the initial position to the retracted position in the sheet discharge reversing means 6, the state in which the sheet S is held is switched from the first state to the third state by the switching means.

  As described above, in the present embodiment, when the drive roller 62 moves from the initial position to the retracted position, the third state in which the sheet S is held by the first holding portion N1 and the third holding portion N3 is described. After forming, it is held by the third holding portion N3. As a result, when the driving roller 62 is moved to switch the nipping portion in which the sheet S is nipped, it is possible to suppress the sheet S from falling off from the sheet discharge reversing means 6.

  In FIG. 8D, the drive roller 62 is moved to the retracted position and stopped for a certain period of time as in FIG. 8C, and the rear end Re of the sheet S is conveyed by the first nip N1. 6 is a schematic view showing a state in which the conveyance of the sheet S is temporarily stopped. At this time, the sheet S is nipped by the third nipping portion N3 formed by the sheet discharge roller 61 and the reversing roller 63, and the sheet S is held in a state in which the conveyance of the sheet S is stopped. The rear end Re of the sheet S nipped by the third nipping portion N3 is moved to the retracted position by the weight and rigidity of the sheet S or the position and angle at which the sheet S is nipped by the third nipping portion N3. It moves above the roller 62. In this state, the drive roller 62 starts moving again from a state where it has stopped for a certain period of time, and the sheet discharge roller 61 is moved from the lower surface side of the sheet S nipped by the third nipping portion N3, that is, the first surface side of the sheet S. By approaching the reversing roller 63, it moves from the retracted position to the initial position.

  FIG. 8E is a schematic view showing the state of the sheet S in the process of moving again from the retraction position to the initial position from the retraction position where the drive roller 62 which has moved to the retraction position where the movement amount is maximum and stopped for a certain time. is there. FIG. 8F is a schematic view showing the state of the sheet S when the drive roller 62 moves to the initial position.

  As shown in FIG. 8E, the drive roller 62 starts moving to the initial position so as to spread between the sheet discharge roller 61 and the reversing roller 63, whereby the sheet S is reversed with the drive roller 62. The roller 63 is nipped by the second nipping portion N2 formed in contact therewith. That is, the sheet S is nipped by the second nipping portion N2 in a second state in which the first surface is in contact with the drive roller 62 and the second surface is in contact with the reversing roller 63, and is conveyed in the second direction. At this time, the third nipping portion N3 formed by the abutment of the reverse roller 63 and the sheet discharge roller 61 is eliminated, and the first nipping portion N1 is formed by the contact of the driving roller 62 and the sheet discharge roller 61. It is done.

  As described above, in the present embodiment, the trailing edge Re of the sheet S is conveyed in the first direction at the first sandwiching portion N1 while the movement of the driving roller 62 is stopped for a certain period of time at the retracted position. Therefore, the drive roller 62 moved to the retracted position is located below the sheet S in the direction of gravity with respect to the rear end Re of the sheet S nipped by the third nipping portion N3. That is, when moving from the retracted position to the initial position, the drive roller 62 moves from the lower surface side of the sheet S to form the second holding portion N2, and stably holds the sheet S in the second holding portion N2. be able to. As a result, it is possible to suppress the decrease in the sheet transportability.

  Further, in the present embodiment, the sheet discharge reversing means 6 has been described in which the contact portion 61b of the sheet discharge roller 61, the contact portion 62b of the drive roller 62, and the contact portion 62b of the reversing roller 63 are respectively opposed. However, the present invention is not limited to this, and a comb-tooth roller in which the contact portion 61b of the discharge roller 61 of the discharge reversing means 6, the contact portion 62b of the drive roller 62, and the contact portion 62b of the reversing roller 63 are alternately arranged in a comb shape. The configuration of

(Example 2)
In the first embodiment, using three rollers, the sheet discharge roller 61, the drive roller 62, and the reverse roller 63, the pinching portion in which the sheet S is pinched is switched from the first pinching portion N1 to the second pinching portion N2. Explained. On the other hand, in the second embodiment, in addition to the sheet discharge roller 161, the drive roller 162, and the reverse roller 163, the nipping portion in which the sheet S is nipped by using the sheet discharge reversing means 106 provided with the sub roller 174 is The second holding portion N12 is switched to the second holding portion N12. The configuration of the present embodiment is the same as that of the first embodiment except that the sub roller 174 is provided in the vicinity of the sheet discharge roller 161 of the sheet discharge reversing means 106. Therefore, in the present embodiment, the description of the same parts as in the first embodiment will be omitted, and differences from the first embodiment will be mainly described using FIGS. 9 and 10A to 10F.

  FIG. 9 is a schematic view for explaining the configuration of the discharge reversing unit 106 when the sheet S is transported in the discharge reversing unit 106 in which the sub roller 174 is provided in the vicinity of the discharge roller 161. As shown in FIG. 9, in the present embodiment, a sub roller 174 as an auxiliary rotating member is provided in the vicinity of the sheet discharge roller 161. The sheet discharge roller 161 and the sub roller 174 are rotatably held by the sheet discharge roller holder 175 (first holding unit). Further, the sheet discharge roller holder 175 is rockably urged against the drive roller 162 by a spring 181 as an urging member provided in the main body 2. When the discharge roller 161 is biased with respect to the drive roller 162, the discharge roller 161 and the drive roller 162 are in contact with each other to form a first sandwiching portion N11.

  FIG. 10A is a schematic view showing a state immediately before the operation of moving the drive roller 162 is started when the sheet S on which the image is formed on the first surface is conveyed to the first holding unit N11. At this time, the drive roller 62 is rotating in one direction at the initial position (first position). The sheet S is conveyed in the first direction with the first surface in contact with the sheet discharge roller 161 and the sub roller 174 and the second surface in contact with the drive roller 162 (first state). As shown in FIG. 10A, the drive roller 162 starts moving away from the sheet discharge roller 161 and the reverse roller 163 before the trailing edge Re of the sheet S is conveyed by the first nip N11. . That is, the drive roller 162 starts moving before the trailing edge Re of the sheet S leaves the drive roller 162.

  FIG. 10B is a schematic view showing a state where the drive roller 162 has started to move from the initial position. In the state of FIG. 10B, the drive roller 162 and the discharge roller 161 are in contact with each other via the sheet S to form the first sandwiching portion N11, and the drive roller 162 and the sub roller 174 are in contact with each other. The sandwiching portion N14 is formed. At this time, the sheet S is nipped by two places of the first nipping portion N11 and the fourth nipping portion N14, and is conveyed in a first direction which is a direction in which the sheet S is discharged from the sheet discharge reversing means 106. The sub roller 174 is provided on the upstream side of the paper discharge roller 161 in the first direction, and in the state of FIG. 10B, the first surface of the sheet S is the paper discharge roller 161 and the sub roller 174. The sheet is conveyed, with the second surface in contact with the driving roller 162.

  FIG. 10C is a schematic diagram showing a state in which the drive roller 162 moves to the retracted position (second position) where the movement amount of the drive roller 62 is maximum, and the movement of the drive roller 62 is stopped for a certain period of time FIG. In the state of FIG. 10C, the drive roller 62 contacts the sub roller 174 in a state in which the movement is stopped for a certain period of time to form the fourth pinching portion N14, and the reverse roller 163 and the discharge roller 161 are the sheet S. , And form a third holding portion N13. At this time, the first surface of the sheet S is in contact with the sheet discharge roller 161 and the sub roller 174, and the second surface is in contact with the drive roller 162 and the reverse roller 163, and is sandwiched by the third pinching portion N13 and the fourth pinching portion N14. In the second state (third state), the sheet is conveyed in the first direction.

  FIG. 10D is a schematic view showing a state in which the conveyance of the sheet S is temporarily stopped after the rear end Re of the sheet S is conveyed by the fourth holding unit N14. At this time, the sheet S is nipped by the third nipping portion N13 formed by the sheet discharge roller 161 and the reversing roller 163, and the sheet S is held in a state in which the conveyance of the sheet S is stopped.

  Further, as shown in FIG. 10D, the rear end Re of the sheet S nipped by the third nipping portion N13 has the weight and rigidity of the sheet S or the sheet S nipped by the third nipping portion N13. It moves upward than the drive roller 162 moved to the retracted position depending on the position, the angle, and the like. Therefore, the drive roller 162 moves from the retracted position to the initial position by approaching the sheet discharge roller 161 and the reverse roller 163 from the lower surface side of the sheet S sandwiched by the third sandwiching portion N13, that is, the first surface side of the sheet S. Moving.

  As described above, also in the present embodiment, when the drive roller 162 is moved from the initial position to the retracted position in the discharged sheet reversing means 106, the sheet S is held by the switching means as in the first embodiment. The state of 1 is switched to the third state. As a result, when the drive roller 162 is moved to switch the nipping portion in which the sheet S is nipped, it is possible to suppress the sheet S from falling off the discharged sheet reversing means 106.

  FIG. 10E is a schematic view showing the state of the sheet S in the process of the drive roller 162 moving from the retracted position to the initial position. As shown in FIG. 10E, the drive roller 162 starts moving to the initial position so as to spread between the sheet discharge roller 161 and the reverse roller 163. The drive roller 162 moves to the initial position from the lower surface side of the sheet S. Therefore, when the operation of moving the drive roller 162 starts, the sheet S is formed by the second pinching portion N12 formed by the drive roller 162 and the reverse roller 163 in contact. It is pinched. That is, the sheet S is nipped by the second nipping portion N12 in a second state in which the first surface is in contact with the drive roller 162 and the second surface is in contact with the reverse roller 163, and is conveyed in the second direction. At this time, the third nipping portion N13 formed by bringing the discharge roller 161 and the reverse roller 163 into contact with each other is eliminated, and the first nipping portion N11 formed by the driving roller 162 and the discharge roller 161 is formed again. Ru.

  FIG. 10F is a schematic view showing the state of the sheet S when the drive roller 162 moves to the initial position. At this time, the fourth nipping portion N14 formed by the contact of the drive roller 162 and the sub roller 174 is eliminated, and the second nipping portion N12 is formed by the contact of the drive roller 162 and the reverse roller 163. . When the movement operation of the drive roller 162 is completed, the sheet S held by the third holding unit N13 is held by the second holding unit N12 formed by the contact of the drive roller 162 and the reverse roller 163. That is, the sheet S is nipped by the second nipping portion N12 in a second state in which the first surface is in contact with the drive roller 162 and the second surface is in contact with the reverse roller 163, and is conveyed in the second direction.

  As described above, also in the present embodiment, with the drive roller 62 moved to the retracted position and the movement of the drive roller 62 stopped at the retracted position for a certain period of time, the rear end Re of the sheet S in the fourth gripping portion N14 Are transported in the first direction. As a result, as in the first embodiment, the sheet S can be stably held by the second holding portion N2, and a decrease in the sheet transportability can be suppressed.

  Furthermore, in the present embodiment, after the rear end Re of the sheet S is conveyed in the first direction in the fourth holding unit N14, the sheet S is held by the third holding unit N13, and the conveyance of the sheet S is stopped. It is held in the state. As described above, the drive roller 62 is moved with respect to the sheet S in a state in which the conveyance is stopped, the second pinching portion N12 is formed, and the sheet S is conveyed in the second direction. The conveyance of S can be resumed, and the conveyance of the sheet S can be stabilized.

  Also in the present embodiment, the drive roller 162 is moved by the switching means including the drive roller holder 65, the cam 67, the cam shaft 68, and the cam drive portion 69, so that the sheet S is held in the second position. The state of 1 is switched to the second state.

  Further, in the configuration of the present embodiment, by providing the sub roller 174, the transportability of the sheet S can be made favorable when the drive roller 62 moves from the initial position to the retracted position. This is because, in the present embodiment, when the drive roller 162 moves from the initial position to the retracted position, the first holding portion N11 and the fourth holding portion N14 contact the discharge roller 161 and the sub roller 174 via the sheet S. By forming In the configuration in which the sheet S is held by the two holding portions of the first holding portion N11 and the fourth holding portion N14, the sheet S is held at two positions of the first holding portion N1 and the third holding portion N3 in the first embodiment. Compared to the configuration, the curvature of the sheet S when the sheet S is held is smaller. Thereby, the transport resistance of the sheet S can be reduced, and the transportability can be further improved.

  In this embodiment, a sheet discharge reversing means is provided with a sub-roller 174 as an auxiliary rotating member in the vicinity of the sheet discharge roller 161 in the first direction in which the sheet S is conveyed and on the upstream side of the sheet discharge roller 161 106 has been described. However, the present invention is not limited to this, and as shown in FIG. 11, the sub roller 176 as an auxiliary rotating body is located in the vicinity of the reversing roller 163 with respect to the first direction in which the sheet S is transported. You may provide. Even in such a configuration, the same effect as that of this embodiment can be obtained.

[Modification 1]
Further, as shown in FIGS. 12 (a) to 12 (f), the same effect as that of the present embodiment can be obtained also in the sheet discharge reversing means 206 provided with a plurality of auxiliary rotating members. 12A to 12F, a sub roller 274 as an auxiliary rotating body is provided on the upstream side of the sheet discharge roller 261 with respect to the first direction in which the sheet S is transported, and the sub roller 276 is provided on the upstream side of the reversing roller 263. It is a schematic diagram explaining the modification 1 of a present Example which provided. The configuration of the sheet discharge reversing means 206 of this embodiment is substantially the same as the sheet discharge reversing means of FIG. 9 except that the sub roller 276 is provided on the upstream side of the reversing roller 263, and the common parts will be described. Omit.

  The sub-rollers 274 and the sub-rollers 276 in the first modification are arranged in the same manner as the sub-rollers 174 in this embodiment in a state of being biased with respect to the driving roller 262. That is, the sheet discharge roller 261 and the sub roller 274 are rotatably held by the sheet discharge roller holder 275 (first holding unit). The reverse roller 263 and the sub roller 276 are rotatably held by a reverse roller holder 277 (second holding unit). The sheet discharge roller holder 275 and the reverse roller holder 277 are swayably urged against the drive roller 262 by springs (not shown) as urging members provided in the main body 2. Thus, in a state before the drive roller 262 moves, the sheet discharge roller 261 contacts the drive roller 262 to form the first sandwiching portion N21, and the reverse roller 263 contacts the drive roller 262 and the second sandwiching portion Form N22.

  FIG. 12A is a schematic view showing a state immediately before the operation of moving the drive roller 62 is started when the sheet S on which the image is formed on the first surface is conveyed to the first holding unit N21. At this time, the drive roller 62 is rotating in one direction at the initial position (first position). The sheet S is conveyed in the first direction with the first surface in contact with the discharge roller 261 and the sub roller 274 and the second surface in contact with the drive roller 262 and the sub roller 276 (first state). There is. As shown in FIGS. 12A and 12B, the drive roller 262 separates from the sheet discharge roller 261 and the reverse roller 263 before the trailing edge Re of the sheet S is conveyed by the first holding unit N21. Start moving in the direction. That is, the drive roller 262 starts moving before the trailing edge Re of the sheet S leaves the drive roller 262.

  FIG. 12B is a schematic view showing a state where the drive roller 262 has started to move from the initial position. In the state of FIG. 12B, the drive roller 262 and the discharge roller 261 come in contact with each other via the sheet S to form the first sandwiching portion N21, and the drive roller 262 and the sub roller 274 come in contact with each other. A sandwiching portion N24 is formed. At this time, the sheet S is nipped by two places of the first nipping portion N21 and the fourth nipping portion N24, and is conveyed in a first direction which is a direction in which the sheet S is discharged from the sheet discharge reversing means 206. Note that the sub roller 274 is provided on the upstream side of the discharge roller 261 in the first direction, and in the state of FIG. 12B, the sheet S has the first surface being the discharge roller 261 and the sub roller 274. The sheet is conveyed, with the second surface in contact with the driving roller 262.

  FIG. 12C is a schematic view showing a state in which the drive roller 262 moves to the retracted position where the movement amount of the drive roller 262 is maximum, and the movement of the drive roller 262 is stopped for a certain time. In the state of FIG. 12C, the drive roller 262 stops moving for a certain period of time and contacts the sub roller 274 to form the fourth pinching portion N24, and contacts the sub roller 276 to form the fifth pinching portion N25. doing. Further, the reverse roller 263 and the sheet discharge roller 261 are in contact with each other through the sheet S to form a third pinching portion N23.

  At this time, the sheet S has the first surface in contact with the sheet discharge roller 261 and the sub roller 274, the second surface in contact with the drive roller 262 and the reverse roller 263, and is held by the third holding portion N23 and the fourth holding portion N24. In the second state (third state), the sheet is conveyed in the first direction. As described above, when the driving roller 262 is moved from the initial position to the retracted position in the discharge reversing unit 206, the switching unit switches the state in which the sheet S is held from the first state to the third state. .

  FIG. 12D is a schematic view showing a state in which the conveyance of the sheet S is temporarily stopped after the rear end Re of the sheet S is conveyed by the fourth holding unit N24. At this time, the sheet N is nipped by the third nipping portion N23 formed by the sheet discharge roller 261 and the reversing roller 263, and the sheet S is held in a stopped state. Further, the rear end Re of the sheet S nipped by the third nipping portion N23 is moved to the retracted position depending on the weight and rigidity of the sheet S or the position and angle at which the sheet S is nipped by the third nipping portion N23. It moves above the drive roller 262. Therefore, the drive roller 262 moves from the retracted position to the initial position by approaching the sheet discharge roller 261 and the reverse roller 263 from the lower surface side of the sheet S sandwiched by the third sandwiching portion N13, that is, the first surface side of the sheet S. Moving.

  As described above, when the driving roller 262 moves from the initial position to the retracted position, the sheet S is nipped by the two nipping portions, and then the sheet S is discharged by nipping by the third nipping portion N23. It is possible to suppress dropout from the paper reversing means 206.

  FIG. 12E is a schematic view showing the state of the sheet S in the process of moving again from the retraction position to the initial position from the retraction position where the driving roller 262 moved to the retraction position where the movement amount is maximum and stopped for a predetermined time. As shown in FIG. 12E, the drive roller 262 starts moving to an initial position so as to spread between the sheet discharge roller 261 and the reverse roller 263. At this time, the third pinching portion N23 formed by the abutment of the reverse roller 263 and the sheet discharge roller 261 is eliminated. Then, while the fifth sandwiching portion N25 is formed, the drive roller 262 and the discharge roller 261 abut each other to form a first sandwiching portion N21, and the drive roller 262 and the reverse roller 263 abut each other to perform a second sandwiching operation. The part N22 is formed.

  Since the driving roller 262 moves from the lower surface side of the sheet S to the initial position, in the state of FIG. 12E, the sheet S is sandwiched by the fifth sandwiching portion N25 and the second sandwiching portion N22, and in the first direction. Are transported in a second direction, which is the opposite direction. That is, the sheet S is conveyed in the second direction with the first surface in contact with the sheet discharge roller 261 and the drive roller 262 and the second surface in contact with the sub roller 276 and the reverse roller 263.

  FIG. 12F is a schematic view showing the state of the sheet S when the driving roller 262 completes movement to the initial position and the sheet S is conveyed to the second holding unit N22. At this time, the fourth pinching portion N24 and the fifth pinching portion N25 are eliminated, and the sheet S is in a second state in which the first surface is in contact with the drive roller 262 and the second surface is in contact with the reverse roller 263. The sheet is held by the second holding portion N22 and conveyed in the second direction. As described above, when the driving roller 262 is moved from the retracted position to the initial position in the sheet discharge reversing means 206, the state in which the sheet S is held is switched from the third state to the second state by the switching means. .

  As described above, even in the configuration of the modification, it is possible to obtain the same effect as that of the present embodiment. Furthermore, in the configuration of the modified example, by providing a plurality of auxiliary rotating members, the sheet S is transported both when the drive roller 262 moves from the initial position to the retracted position and when moving from the retracted position to the initial position. It is possible to reduce the resistance. Thereby, the transportability of the sheet S can be further improved.

[Modification 2]
13A to 13F show a modification of this embodiment in which the retraction position of the drive roller 262 is set on the upstream side of the retraction position in the first modification with respect to the first direction which is the transport direction of the sheet S. FIG. 5 is a schematic view for explaining an example 2; In the following description, parts that are the same as in the first modification will be assigned the same reference numerals and descriptions thereof will be omitted.

  FIG. 13C is a schematic view showing a state in which the drive roller 262 moves to the retracted position where the movement amount of the drive roller 262 is maximum, and the movement of the drive roller 262 is stopped for a certain time. In the state shown in FIG. 13C, the drive roller 262 stops moving for a certain period of time and contacts the sub roller 274 to form the fourth pinching portion N24, and the reversing roller 263 and the discharge roller 261 via the sheet S. And abut on each other to form a third holding portion N23.

  At this time, as shown in FIG. 13C, in the second modification, the moving amount of the drive roller 262 is made larger than that of the first modification, and the fifth to the drive roller 262 and the sub roller 276 are formed in contact. The clamping portion N25 is eliminated. That is, the first surface of the sheet S is in contact with the sub roller 274 and the discharge roller 261, the second surface is in contact with the drive roller 262 and the reverse roller 263, and the sheet S is held by the fourth holding portion N24 and the third holding portion N23. In the third state, the sheet is transported in the first direction. Here, as compared with the first modification, the second modification has a fourth pinching portion N24 formed by bringing the drive roller 262 and the sub roller 274 into contact with each other in the first direction by increasing the moving amount of the drive roller 262. It is set more upstream.

  FIG. 13D is a schematic view showing a state in which the conveyance of the sheet S is temporarily stopped after the rear end Re of the sheet S is conveyed by the fourth holding unit N24. At this time, the sheet S is held in a stopped state by being pinched by the third pinching portion N23 formed by the sheet discharge roller 261 and the reversing roller 263. In the second modification, by setting the position of the fourth holding portion N24 on the upstream side with respect to the first direction, as shown in FIG. 13 (d), the position of the rear end Re of the sheet S is It is on the downstream side of the position in the first modification with respect to the direction 2.

  The rear end Re of the sheet S nipped by the third nipping portion N23 is driven to move to the retracted position by the weight and rigidity of the sheet S or the position and angle at which the sheet S is nipped by the third nipping portion N23. It moves above the roller 262. In this state, the drive roller 262 starts moving again from the state where it has stopped for a certain period of time, and the discharge roller 261 from the lower surface side of the sheet S sandwiched by the third sandwiching portion N23, that is, the first surface side of the sheet S. And moves to the initial position from the retracted position by approaching the reverse roller 263. Then, when the movement operation of the drive roller 262 is started, the sheet S is nipped by the fifth nipping portion N25 formed by the contact of the drive roller 262 and the sub roller 276, and is conveyed in the second direction.

  According to the configuration of the second modification, the sheet S sandwiched in the fifth sandwiching portion N25 is transported in the second direction before the second sandwiching portion N22 is formed and the sheet S is transported in the second direction. It is possible. As a result, the sheet S can be reliably held in the second holding portion N22 and conveyed in the second direction, and the conveyance of the sheet S at the time of reverse can be improved. Also in the configuration of the second modification, the same effect as the first embodiment and the second embodiment can be obtained.

(Example 3)
In the first and second embodiments, the configuration has been described in which the movement of the drive roller 62 is stopped for a certain period of time at the retracted position where the movement amount of the drive roller 62 is maximum. On the other hand, in the third embodiment, as shown in FIGS. 14 (a) to 14 (g) and FIGS. 15 (a) to 15 (e), it is at a position different from the retracted position where the moving amount of the drive roller 262 is maximum. The configuration for stopping the movement of the drive roller 262 for a fixed time will be described. Since the present embodiment is the same as the second modification of the second embodiment except for the movement operation of the drive roller 262, the same reference numerals are given to the portions common to the second modification and the description is omitted. .

  The operation of the drive roller 262 in FIGS. 14A and 14B is the same as in the first and second modifications of the second embodiment, and therefore the description thereof is omitted.

  FIG. 14C shows the stop position (third position) before reaching the retracted position (second position) where the movement amount of the drive roller 262 is maximum after the drive roller 262 starts moving from the initial position. Is a schematic view showing a state in which the movement is stopped for a certain period of time. FIG. 14D is a schematic view for explaining a state in which the drive roller 262 has stopped moving at the stop position, and the rear end Re of the sheet S is conveyed at the fourth holding portion N24. FIG. 14E is a schematic view for explaining a state in which the drive roller 262 has moved to the retracted position after the rear end Re of the sheet S is conveyed in the fourth holding unit N24.

  As shown in FIGS. 14 (c) to 14 (e), in the present embodiment, the drive roller 262 stops moving for a certain period of time at a position where the moving amount of the driving roller 262 is not maximum. It is being transported. When the sheet S is nipped by the third nipping portion N23 after the rear end Re of the sheet S is transported in the fourth nipping portion N24, the sheet S is held in a state in which the conveyance is stopped at the third nipping portion N23. .

  At this time, the rear end Re of the sheet S may not move upward relative to the drive roller 262 depending on the weight and rigidity of the sheet S, or the position and angle at which the sheet S is nipped by the third nipping portion N23. obtain. In this state, when the drive roller 262 starts moving toward the initial position again, from the upper surface side of the sheet S nipped by the third nipping portion N23, that is, from the second surface side of the sheet S in FIG. There is a possibility that the sheet discharge roller 261 and the reverse roller 263 may be approached. As a result, the sheet S is again pinched by the fourth pinching portion N24 and the first pinching portion N21, whereby the sheet S is discharged in the first direction and then discharged from the sheet discharge reversing means 206. There is a fear.

  Therefore, in the present embodiment, after the trailing edge R2 of the sheet S is conveyed in the first direction in the fourth holding unit N24 in a state where the driving roller 262 is stopped for a predetermined time, the driving roller 262 is retracted. Move to position then move to initial position. As a result, as shown in FIG. 14E, the drive roller 262 moves to the lower side with respect to the rear end Re of the sheet S in the gravity direction. Thereafter, the drive roller 262 moves to the initial position without stopping for a certain period of time at the retracted position where the amount of movement is maximum.

  FIG. 14F is a schematic view for explaining a state in which the drive roller 262 moves from the retracted position to the initial position, and FIG. 14G shows a state in which the drive roller 262 stops moving at the initial position. It is a schematic diagram explaining. The operation of the drive roller 262 in FIGS. 14 (f) to 14 (g) is the same as the movement operation of the drive roller 262 in FIGS. 13 (e) to 13 (f), and thus the description thereof is omitted.

  As described above, in the configuration of the present embodiment, after the driving roller 262 is stopped for a predetermined time at the stopping position between the initial position and the retreating position, the retreating position at which the moving amount of the driving roller 262 is maximum from the stopping position. Drive roller 262 is moved. With this configuration, the drive roller 262 moved to the retracted position can be easily moved from the lower surface side of the sheet S to the initial position, and the transportability of the sheet S is stabilized, thereby suppressing the deterioration of the transportability of the sheet S. Can.

  Next, the movement operation of the drive roller 262 in this embodiment will be described using FIGS. 15 (a) to 15 (e). In FIGS. 15 (a) to 15 (e), the configuration of the toothless gear and the solenoid transmitting the drive to the cam 267 is the same as the configuration of the cam drive unit 69 in the first and second embodiments. Will be described with the same reference numerals as in the first embodiment and the second embodiment.

  FIG. 15A is a schematic view of the sheet discharge reversing means 206 before the operation of moving the drive roller 262 is viewed from the axial direction of the drive roller 262. FIG. The position of the drive roller 262 at this time is the initial position, and the drive roller 262 rotates in only one direction in response to the driving force from the drive source at the initial position.

  In the state of FIG. 15A, when the solenoid 69a is energized to release the lock of the tooth missing gear 69b, the cam 267 rotates in the direction of the arrow A (clockwise). At this time, the cam contact portion 265 c of the drive roller holder 265 abuts against the cam 267 by being biased by a spring (not shown). Then, as the cam 267 rotates in the direction of arrow A (clockwise), the drive roller holder 265 rotates about the fulcrum 266 in the direction of arrow B (counterclockwise). Along with this, the drive roller 262 held at both ends by the drive roller holder 265 moves in the direction (arrow B direction in the drawing) away from the sheet discharge roller 261 and the reverse roller 263.

  FIG. 15B is a schematic view of the sheet discharge reversing means 206 in a state in which the drive roller 262 and the sheet discharge reversing guide 264 are moved by the rotation of the cam 267, as viewed from the axial direction of the drive roller 262. FIG. 15C is a schematic view of the sheet discharge reversing means when the drive roller 262 moves to the stop position by the rotation of the cam 267, as viewed from the axial direction of the drive roller 262.

  At this time, the cam contact portion 265 c of the drive roller holder 265 is in contact with the angle E at which the cam 267 has the same diameter. In this state, even if the cam 267 continues rotating, the movement of the drive roller 262 can be stopped at the stop position for a certain period of time by the angle E. Further, by appropriately setting the rotational speed of the cam 267 and the angle E, the time for stopping the movement of the drive roller 262 at the stop position can be arbitrarily set. In the present embodiment, the movement of the drive roller 262 can be stopped for a certain period of time by the stopping means formed by the drive roller holder 265 having the cam abutting portion 265 c and the cam 267.

  Thereafter, as shown in FIG. 15D, when the cam 267 rotates in the direction of the arrow A (clockwise), the cam contact portion 265c of the drive roller holder 265 abuts on the largest diameter portion of the cam 267. The drive roller holder 265 rotates in the direction of the arrow B in the figure. Thus, the drive roller 262 moves to the retracted position where the amount of movement of the drive roller 262 is maximum. When the cam 267 further rotates in the direction of arrow A (clockwise), the largest diameter portion of the cam 267 passes from the cam contact portion 265c of the drive roller holder 265, whereby the drive roller holder 265 centers on the fulcrum 266. It rotates in the direction of arrow C (clockwise).

  As shown in FIG. 15E, when the cam 267 further rotates in the direction of arrow A (clockwise), the drive roller holder 265 rotates about the fulcrum 266 in the direction of arrow C (clockwise). As a result, the drive roller 262 approaches the sheet discharge roller 261 and the reverse roller 263 and moves from the retracted position to the initial position. When the cam 267 is further rotated from the state of FIG. 15 (e) and the drive roller 262 returns to the initial position, the drive is released by the tooth missing gear 69b, and the rotation of the cam 267 is stopped. At this time, since the solenoid 69a has already been de-energized, the cam 267 is locked at the position where the drive is released. That is, also in the present embodiment, a series of operations of the sheet discharge reversing means 206 for moving the drive roller 262 is a series of operations which occur during one rotation of the cam 267 by the cam drive unit 69.

(Example 4)
In the first to third embodiments, the configuration in which the movement of the drive roller 62 is temporarily stopped by the cam 67 has been described. On the other hand, in the fourth embodiment, as shown in FIG. 16, the paper discharge reversing means 6 provided with a cam drive unit 100 having a configuration different from that of the first embodiment will be described. The configuration of the present embodiment is the same as that of the first embodiment except for the configuration of the cam drive unit 100, and therefore, the same members and configurations are assigned the same reference numerals and explanation thereof is omitted.

  FIG. 16 is a schematic view for explaining the configuration of the cam drive unit 100 as the stopping means in the present embodiment. As shown in FIG. 16, the non-toothed gear 92 in the cam drive unit 100 includes two non-toothed portions 92 a and 92 b. When the missing tooth portion 92 a or 92 b reaches the position of the input gear 93, the transmission of the drive from the input gear 93 to the missing tooth gear 92 is released. At this time, the tooth-missing gear 92 is biased to rotate in the direction of the arrow in the drawing by biasing means (not shown), but the movable piece 91a of the solenoid 91 engages with the locking portion 92c or the locking portion 92d. In the state, the rotation stops. On the other hand, when the solenoid 91 is energized to release the engagement between the movable piece 91a and the locking portion 92c or the locking portion 92d, the toothless gear 92 rotates in the direction of the arrow in the figure by biasing means (not shown). It meshes with the input gear 93 and the drive is transmitted.

  In this embodiment, the non-toothed portions 92a and 92b are configured to be opposed to the input gear 93 when the drive roller 62 is in the initial position and the retracted position, and the operation of energizing and releasing the solenoid 91 is performed. These two positions can be switched each time it is done. With this configuration, the time for temporarily stopping the movement of the drive roller 62 can be arbitrarily adjusted. Therefore, the variation in the timing at which the conveyance of the sheet S temporarily stops can be grasped by the sensor signal, and the timing at which the sheet S is reversed can be adjusted according to the variation, and the transportability of the sheet S can be improved.

(Example 5)
In the fourth embodiment, the configuration in which the drive roller 62 is temporarily stopped by the cam drive unit 69 having the solenoid 69a and the tooth missing gear 69b has been described. On the other hand, in the fifth embodiment, as shown in FIGS. 17A and 17B and FIGS. 18A to 18D, the sheet discharge reverse including the cam drive unit 200 having a configuration different from that of the first embodiment. The means will be described. The configuration of the present embodiment is the same as that of the first embodiment except for the configuration of the cam drive unit 200, and therefore, the same members and configurations are assigned the same reference numerals and explanation thereof is omitted.

  FIG. 17 (a) is a schematic view showing the configuration of the cam drive unit 200 in the present embodiment, and FIG. 17 (b) is an exploded view of the cam drive unit 200 as viewed from the CC direction in FIG. 17 (a). It is a schematic diagram. In the present embodiment, the drive roller 62 can be moved by the switching means provided with the drive roller holder 65, the cam 67, the cam shaft 68, and the cam drive unit 200.

  As shown in FIGS. 17A and 17B, the cam drive unit 200 as the stopping means includes the drive gear 201, the drive disc 202, the link lever 203, the stopper disc 204, and the biasing cam 205. , A biasing lever 216, and a solenoid 207.

  As shown in FIG. 17A, the biasing surface 205 a provided on the biasing cam 205 and the biasing surface 205 b are rotatable biasing levers that are biased toward the biasing cam 205 by the spring 210. It is comprised by the angle which can oppose and contact | abut with 216. FIG.

  As shown in FIG. 17B, the cam 67, the drive disk 202, and the biasing cam 205 are fixed to the cam shaft 68 in a state where they can rotate integrally. The drive disk 202 is provided with a cylindrical projection 202a, and the link lever 203 is rotatably held by the projection 202a. The link lever 203 is biased by a spring 209, and the engaging portion 203a of the link lever 203 can be engaged with the recess 201a provided on the inner peripheral portion of the drive gear 201 by the biasing force of the spring 209. is there. Further, the cylindrical projection 203 b provided on the link lever 203 is fitted with the slit 204 a provided on the stopper disk 204. The outer peripheral surface of the stopper disk 204 is provided with a locking portion 204b capable of locking the rotation of the stopper disk 204 by engaging with a movable piece 207a provided to the solenoid 207, and a locking portion 204c. There is.

  Here, the operation of the cam drive unit 200 when moving the drive roller 62 will be described using FIGS. 18 (a) to 18 (d). 18 (a) to 18 (d) are schematic views of the sheet discharge reversing means 6 in each state as viewed from the axial direction of the drive roller 62. FIG.

  18A shows an initial position (first position) where the drive roller 62 can convey the sheet S together with the sheet discharge roller 61 or the reverse roller 63 before the solenoid 207 is energized. It is a schematic diagram which shows the state of the cam drive part 200 at the time of positioning. As shown in FIG. 18A, in a state in which the movable piece 207a of the solenoid 207 and the locking portion 204b of the stopper disk 204 are engaged, the engaging portion 203a of the link lever 203 is an inner portion of the drive gear 201. It hold | maintains in the state which does not engage with the recessed part 201a of a surrounding surface. At this time, the drive gear 201 receives the drive force transmitted from the input gear 93 and rotates in the direction of the arrow A in the figure, but since the engaging portion 203a and the recess 201a are not engaged, Power is not transmitted. At this time, one biasing surface 205 a of the biasing cam 205 is in contact with the biasing lever 216 so as to face it.

  FIG. 18B is a schematic view showing a state in which the solenoid 207 is energized to release the engagement between the movable piece 207a and the locking portion 204b and release the locking of the stopper disk. In this state, the link lever 203 is pivoted in the illustrated arrow B direction by the biasing force of a spring 209 which is a tension spring. Further, the stopper disc 204 is rotated in the direction of the arrow A in the figure by the application of force by the projection 203b fitted to the slit 204a.

  When the link lever 203 is rotated and the engaging portion 203a engages with the recess 201a provided on the inner peripheral surface of the drive gear 201, the link lever 203 held by the projection 202a, together with the drive gear 201, is in the direction of arrow A. To rotate. As a result, a rotational force is applied to the drive disk 202, and the drive gear 201, the link lever 203, and the drive disk 202 rotate in the direction of the arrow A in the drawing. At this time, as the drive disk 202 rotates, the cam 67 rotates via the cam shaft 68 fixed so as to rotate integrally with the drive disk 202, and the drive roller 62 retracts from the initial position (second position Start moving to position).

  FIG. 18C is a schematic view showing a state in which the movable piece 207a of the solenoid 207 deenergized and the other locking portion 204c of the stopper disk 204 are engaged. When the stopper disk 204 is locked by the engagement of the movable piece 207a and the locking portion 204c, the projection 203b of the link lever 203, which rotates in the direction of the arrow A with the drive gear 201, moves along the slit 204a. Do. As a result, the link lever 203 is pivoted in the direction of the arrow C, and the engagement between the engaging portion 203a of the link lever 203 and the recess 201a of the inner peripheral surface of the drive gear 201 is released. Rotation stops. At this time, the cam shaft 68 and the cam 67 also stop rotating, and the drive roller 62 stops moving at the retracted position.

  FIG. 18D is a schematic view showing a state in which the drive roller 62 stops moving at the retracted position. At this time, as in FIG. 18A, since the engagement between the recess 201a of the drive gear 201 and the engagement portion 203a of the link lever 203 is released, the rotational force of the drive gear 201 is not transmitted to the cam 67. . In this state, when the solenoid 207 is energized again, the cam 67 rotates to be in the state shown in FIG. 18A, and the drive roller 62 moves from the retracted position to the initial position.

  As described above, in the configuration of the present embodiment as well as the first to fourth embodiments, the drive roller 62 moves from the initial position to the retracted position during one rotation of the cam 67 by the cam drive unit 200, and A series of operations are performed to move from the retracted position to the initial position. In addition, with the configuration of the cam drive unit 200, it is possible to stop the movement of the drive roller 62 at a predetermined timing. FIG. 19 is a schematic diagram for explaining another configuration of the present embodiment. An electric clutch 213 as shown in FIG. 19 or a dedicated motor (not shown) is provided to control the rotation of the cam 67, and controls movement start or movement stop of the drive roller 62 at a predetermined timing. It is good also as composition to do.

(Other embodiments)
As mentioned above, although the Example at the time of using an image forming device as a sheet conveyance device was described, the sheet conveyance device in the present invention is not limited to this. The present invention can be used as long as it is an apparatus for changing the transport direction of the sheet S from the first transport direction to the second transport direction, and the same effect as that of the embodiment of the present invention can be obtained. That is, as shown in FIG. 20, the present invention can be applied to an image reading apparatus for reading an image of a sheet S being conveyed, and the same effect can be obtained.

  An image reading apparatus 401 as a sheet conveying apparatus in the present embodiment includes an image reading unit 404 that reads an image of a sheet S being conveyed. The configuration of the sheet discharge reversing means 406 in the present embodiment is the same as that of the first embodiment. Therefore, differences from the first embodiment, such as the configuration of the image reading apparatus 401 and the method of reading the image on both sides of the sheet S, will be mainly described, and the same parts as those of the first embodiment will not be described.

  The sheets S accommodated in the sheet feeding tray 421 as the accommodation portion are fed by the rotation of the feeding roller 430 and separated into individual sheets by the separating means 452. Thereafter, the sheet is conveyed to the image reading unit 404 by the conveyance roller pair 456 and 457 in the first conveyance path 450, and the image reading unit 404 reads the image on the first side of the sheet. The sheet S from which the image on the first side has been read is conveyed to the sheet discharge reversing means 406, and is formed by the driving roller 462 (the first rotating body) and the sheet discharging roller 461 (the second rotating body). It is clamped by the clamping part N41. As the drive roller 462 rotates, the sheet S nipped between the drive roller 462 and the discharge roller 461 is conveyed from the drive roller 462 toward the discharge tray 422 as a stacking unit, and is discharged from the apparatus main body 402 In the direction 1). The drive roller 462 starts moving before the rear end of the sheet S is conveyed to the discharge tray 422 by the drive roller 462 and the discharge roller 461.

  Due to the movement of the drive roller 462, the sheet S nipped by the first nipping portion N41 is nipped by the second nipping portion N42 formed by the drive roller 462 and the reversing roller 463, and from the discharge tray 422 to the second conveyance path It is conveyed in the direction (second direction) toward 451. Thereafter, the sheet S is conveyed again to the image reading unit 404 by the conveyance roller pairs 456 and 457 in the first conveyance path 450, and the image reading unit 404 reads the image on the second side of the sheet S. The sheet S whose images on both sides of the first and second surfaces have been read is conveyed again to the first holding unit N41, conveyed in the first direction by the first holding unit N1, and then discharged to the sheet discharge tray 422. Be done.

  As described above, also in the present embodiment, by moving the drive roller 462 of the sheet discharge reversing means 406, the sheet S nipped by the first nipping portion N41 is not completely discharged from the sheet discharge reversing means 406. , And can be held by the second holding portion N42. Similar to the discharge reversing means 6 of the first embodiment, the discharge reversing means 406 has switching means for switching the nipping state of the sheet S. Therefore, the sheet discharge reversing means 406 starts the pinching portion where the sheet S is pinched from the first pinching portion N41 before the rear end of the sheet S being fed in the first direction is conveyed by the first pinching portion N41. It can switch to the 2nd clamping part N42. As described above, the present invention can be applied to an image reading apparatus that reads an image of a sheet S being conveyed, and the same effect as that of the first embodiment can be obtained.

  Furthermore, although the example in which the present invention is applied to an electrophotographic image forming apparatus is shown in the above embodiment, the present invention is not limited to this, and, for example, an electrophotographic image forming apparatus The present invention may be applied to image forming apparatuses other than the method.

Reference Signs List 1 image forming apparatus 4 image forming unit 65 drive roller holder 67 cam 68 cam shaft 69 cam drive unit 69
61 Ejection roller 62 Drive roller 63 Reversing roller

Claims (20)

A first rotating body that rotates only in one direction, a second rotating body that transports the sheet together with the first rotating body in a first direction by rotating the first rotating body, and A third rotating body for conveying the sheet together with the first rotating body in a second direction different from the first direction by rotating the first rotating body;
The second rotary body is a first surface of the sheet by moving the first rotary body while the sheet is transported in the first direction by the first rotary body and the second rotary body. The first rotating body contacts the second surface of the sheet from a first state in which the first rotating body contacts the second surface opposite to the first surface of the sheet, and The first rotating body is the sheet after the second rotating body is in contact with the first surface of the sheet and the third rotating body is switched to the third state in which the second rotating body is in contact with the second surface of the sheet. Switching means for contacting the first surface and switching to a second state in which the third rotating body contacts the second surface of the sheet;
Stop means for stopping the movement of the first rotating body to convey the rear end of the sheet in the first direction in the first direction by the rotation of the first rotating body in the third state And a sheet conveying apparatus.   The switching means has a first position at which the position of the first rotating body is transported along with the second rotating body or the third rotating body, and a second position where the switching means is retracted from the first position. And the first state and the second state are formed when the first rotating body is positioned at the first position. An image forming apparatus according to claim 1.   The image forming apparatus according to claim 2, wherein the stopping unit stops movement of the first rotating body at any position from the first position to the second position.   The image forming apparatus according to claim 2, wherein the stopping unit stops the movement of the first rotating body at the second position.   4. The apparatus according to claim 2, wherein the stopping means stops movement of the first rotating body at a third position which is between the first position and the second position. Image forming apparatus.   With the stopping means stopping the movement of the first rotating body at the third position, the rear end of the sheet in the first direction is rotated by the rotation of the first rotating body. 6. The image forming apparatus according to claim 5, wherein the switching unit moves the first rotating body from the third position to the first position through the second position after being transported to the second position. apparatus.   The stopping means stops the movement of the first rotating body, and the rear end of the sheet in the first direction is conveyed in the first direction by the rotation of the first rotating body. In the sheet separated from the rotating body, the second rotating body is in contact with the first surface of the sheet, and the third rotating body is in contact with the second surface of the sheet. The image forming apparatus according to any one of claims 1 to 6, wherein the image forming apparatus is held by the third rotating body and the third rotating body.   The second rotating body is in contact with the first rotating body to form a first sandwiching portion for sandwiching a sheet, and the third rotating body is the second rotating body in the circumferential direction of the first rotating body. The sheet conveying apparatus according to any one of claims 1 to 7, wherein a second holding unit for holding the sheet in contact with the first rotating body is formed at a position different from that of the rotating body.   In the third state, a first holding unit is formed by the first rotating body and the second rotating body, and a third holding unit holds the sheet by the second rotating body and the third rotating body. 9. The sheet conveying apparatus according to claim 8, wherein a pinching portion is formed, and a sheet is pinched by the second pinching portion and the third pinching portion.   A first auxiliary rotating body is provided upstream of the second rotating body with respect to the first direction, and in the third state, the sheet is held by the second rotating body and the third rotating body. A third holding unit is formed, a fourth holding unit for holding a sheet is formed by the first rotating body and the first auxiliary rotating body, and a sheet is formed by the third holding unit and the fourth holding unit. 9. The sheet conveying apparatus according to claim 8, wherein the sheet is held.   Providing a first holding portion for holding the first auxiliary rotary body and the second rotary body; and an urging member for urging the first holding portion against the first rotary body. The sheet conveying apparatus according to claim 10, characterized in that:   A second auxiliary rotating body disposed upstream of the third rotating body with respect to the first direction, and a second holding unit for holding the second auxiliary rotating body and the third rotating body The sheet conveying apparatus according to any one of claims 1 to 11, further comprising: an urging member configured to urge the second holding portion against the first rotating body.   The switching means moves the first rotating body so that the first rotating body and the second rotating body are in contact with the first surface of the sheet from the third state. 13. The sheet conveying apparatus according to claim 12, wherein the sheet conveyance device is switched to the second state through a state in which the third rotary body and the second auxiliary rotary body are in contact with the second surface of the sheet.   The sheet conveying apparatus according to any one of claims 1 to 13, wherein the first rotating body rotates in only one direction by receiving a driving force from a driving source.   15. The sheet conveying apparatus according to claim 14, wherein the first rotating body continues to rotate by receiving the driving force from the driving source when moving.   16. The sheet conveying apparatus according to claim 14, wherein the drive source is a drive motor which rotates only in one direction.   The sheet processing apparatus further includes a stacking unit configured to stack the discharged sheets, and in the first direction, the sheet is transported from the first rotating body toward the stacking unit by the first rotating body and the second rotating body. The sheet conveying apparatus according to any one of claims 1 to 16, wherein the sheet conveying direction is a direction in which the sheet is conveyed.   The sheet is conveyed in the first direction by the first conveying path for conveying the sheet toward the first rotating body and the second rotating body, and the first rotating body and the second rotating body. And a second conveyance path for conveying the sheet again to the first conveyance path, and in the second direction, the sheet is transferred from the stacking portion by the first rotating body and the third rotating body. 18. The sheet conveying apparatus according to claim 17, wherein the sheet is conveyed in a direction toward the second conveyance path.   An image comprising: an image forming unit for forming an image on a sheet; and the sheet conveying apparatus according to any one of claims 1 to 18 for conveying the sheet on which the image is formed in the image forming unit. Forming device.   An image reading unit for reading an image of a sheet, and the sheet conveying apparatus according to any one of claims 1 to 18, wherein the image reading unit reads an image of a sheet conveyed by the sheet conveying apparatus. An image reading apparatus characterized by

Images