Patent ID: 8087666

Claim:
A sheet discharge device that discharges a sheet of a recording medium on which an image has been formed to a sheet discharge tray, the sheet discharge device comprising: a rotary shaft that extends in a first direction and has a sheet conveyance center in the first direction; a drive roller group that includes at least two inside drive rollers rotatably arranged on the rotary shaft on either sides of the sheet conveyance center and at least two outside drive rollers rotatably arranged on the rotary shaft on either sides of the inside drive rollers; a driven roller group that includes at least two inside driven rollers and at least two outside driven rollers, the inside driven rollers individually opposing the inside drive rollers to be rotated by the inside drive rollers, the outside driven rollers individually opposing the outside drive rollers to be rotated by the outside drive rollers; at least two end retainers each of which is rotatably attached to the rotary shaft and positioned adjacent to one of the outside drive rollers from a side away from the sheet conveyance center, the end retainers coming into press contact with first near-side-end portions of the sheet being discharged to retain the sheet; and at least two inside retainers each of which is rotatably attached to the rotary shaft and adjacent to one of the inside drive rollers from a side away from the sheet conveyance center, the inside retainers coming into press contact with second near-side-end portions of the sheet being discharged to retain the sheet, each retainer of the end retainers and the inside retainers including a distal end on a side away from the rotary shaft, wherein when the each retainer is in an unretracted orientation, the each retainer extends from the rotary shaft such that the distal end is further away from the rotary shaft than a common tangent of the drive roller group and the driven roller group is, and the end retainers are longer than the inside retainers.