Sheet supporting apparatus and image forming system

1 . A sheet supporting apparatus comprising:

a sheet discharge unit configured to convey a sheet to discharge the sheet;

a conveyance unit including a gripper member configured to engage with a leading edge of the sheet that has been discharged from the sheet discharge unit, the gripper member being disposed in a part of a sheet width direction perpendicular to a sheet discharge direction, the conveyance unit being configured to convey the sheet engaged with the gripper member by moving the gripper member;

a stacking unit on which the sheet that has been conveyed by the conveyance unit is stacked; and

a stiffening unit including an abutment surface configured to abut against the sheet conveyed by the sheet discharge unit toward the gripper member, the stiffening unit being configured to stiffen the sheet by curving the sheet when viewed in the sheet discharge direction, the stiffening unit being disposed in a part of the sheet width direction perpendicular to a sheet discharge direction,

wherein the stiffening unit is provided at a position where at least part of the stiffening unit overlaps the gripper member in the sheet width direction when viewed in the sheet discharge direction.

2 . The sheet supporting apparatus according to claim 1 ,

wherein the abutment surface is configured to abut against an under surface of the sheet conveyed by the sheet discharge unit toward the gripper member, and

wherein the stiffening unit is configured to stiffen the sheet by curving the sheet upward when the sheet is viewed in the sheet discharge direction.

3 . The sheet supporting apparatus according to claim 1 ,

wherein the sheet discharge unit includes a first roller pair and a second roller pair,

wherein the first roller pair includes a first roller and a second roller, the second roller being configured to form a first nip portion by coming into contact with the first roller,

wherein the second roller pair includes a third roller and a fourth roller, the fourth roller being configured to form a second nip portion by coming into contact with the third roller, the second roller pair being provided in alignment with the first roller pair in the sheet width direction, and

wherein the stiffening unit is provided between the first roller pair and the second roller pair in the sheet width direction and at a position at which at least part of the stiffening unit overlaps both the first roller pair and the second roller pair in the sheet discharge direction when viewed in the sheet width direction.

4 . The sheet supporting apparatus according to claim 3 , wherein the abutment surface is arranged above both the first nip portion and the second nip portion.

5 . The sheet supporting apparatus according to claim 4 , further comprising:

a first guide including a first guide surface configured to guide the sheet in the sheet discharge unit; and

a second guide including a second guide surface oppositely arranged above the first guide surface, the second guide surface being configured to guide the sheet in the sheet discharge unit,

wherein the abutment surface is arranged below the second guide surface at a predetermined position in the sheet discharge direction.

6 . The sheet supporting apparatus according to claim 3 ,

wherein the abutment surface is a first abutment surface,

wherein the stiffening unit is a first stiffening unit, and

wherein the sheet supporting apparatus further includes:

a second stiffening unit including a second abutment surface that is configured to abut against the sheet, the second stiffening unit being provided on a side opposite to the second roller pair with respect to the first roller pair in the sheet width direction.

7 . The sheet supporting apparatus according to claim 6 , wherein the second abutment surface is arranged above the first abutment surface.

8 . The sheet supporting apparatus according to claim 6 , further comprising:

a third stiffening unit including a third abutment surface that is configured to abut against the sheet, the third stiffening unit being provided on a side opposite to the first roller pair with respect to the second roller pair in the sheet width direction.

9 . The sheet supporting apparatus according to claim 2 ,

wherein the stiffening unit includes a moving member and an urging member,

wherein the moving member includes the abutment surface, and is configured to be movable in a vertical direction, and

wherein the urging member is configured to urge the moving member upward.

10 . The sheet supporting apparatus according to claim 1 , further comprising:

a first guide including a first guide surface configured to guide the sheet in the sheet discharge unit; and

a second guide including a second guide surface oppositely arranged above the first guide surface, the second guide surface being configured to guide the sheet in the sheet discharge unit,

wherein the abutment surface is arranged above the first guide surface at a predetermined position in the sheet discharge direction.

11 . The sheet supporting apparatus according to claim 1 ,

wherein the conveyance unit includes a belt on which the gripper member is provided,

wherein the belt is supported by a rotary member, and

wherein the gripper member is moved by rotation of the belt.

12 . The sheet supporting apparatus according to claim 11 , wherein the gripper member is configured to engage with the leading edge of the sheet discharged from the sheet discharge unit below a rotation center of the rotary member.

13 . The sheet supporting apparatus according to claim 1 ,

wherein the conveyance unit includes a contact portion configured to come into contact with the leading edge of the sheet engaged with the gripper member, and

wherein, in a case where the leading edge of the sheet engaged with the gripper member comes into contact with the contact portion, engagement of the gripper member with the sheet is released, and the sheet whose engagement with the gripper member has been released is stacked on the stacking unit.

14 . The sheet supporting apparatus according to claim 1 , wherein the sheet discharge direction is a horizontal direction.

15 . An image forming system comprising:

an image forming apparatus configured to form an image on a sheet; and

the sheet supporting apparatus according to claim 1 , the sheet supporting apparatus being configured to receive the sheet on which the image has been formed by the image forming apparatus and discharge the sheet from the sheet discharge unit.

16 . The sheet supporting apparatus according to claim 8 ,

wherein the second stiffening unit is provided at a position where at least part of the second stiffening unit overlaps both the first roller pair and the second roller pair in the sheet discharge direction when viewed in the sheet width direction, the second stiffening unit being configured to stiffen the sheet by curving the sheet upward, and

wherein the third stiffening unit is provided at a position where at least part of the third stiffening unit overlaps both the first roller pair and the second roller pair in the sheet discharge direction when viewed in the sheet width direction, the third stiffening unit being configured to stiffen the sheet by curving the sheet upward.

17 . The sheet supporting apparatus according to claim 6 ,

wherein the second abutment surface is configured to abut against an under surface of the sheet conveyed by the sheet discharge unit toward the gripper member, and

wherein the second stiffening unit is configured to stiffen the sheet by curving the sheet upward when the sheet is viewed in the sheet discharge direction.

18 . The sheet supporting apparatus according to claim 6 , wherein the second stiffening unit is disposed at a position that does not overlap the gripper member in the sheet width direction when viewed in the sheet discharge direction.

19 . The sheet supporting apparatus according to claim 1 ,

wherein the gripper member has an inclined surface, and a downstream end of the inclined surface in the sheet discharge direction is higher than an upstream end of the inclined surface in the sheet discharge direction, and

wherein, in a state in which the gripper member engages with the sheet, the abutment surface of the stiffening unit is disposed above a central position in a height direction of the inclined surface.