Sheet ejection device, and image forming apparatus and post-processing apparatus that are provided therewith

摘要

A sheet ejection device comprises an ejection roller pair (20) which ejects a sheet by a pressure contact portion (N) in which a first roller (21) and a second roller (22) are in pressure contact with each other. In the first roller (21), protrusions (41) that protrude in a roller diameter direction in order to push the back end of the sheet ejected with the rotation of the first roller (21) are formed. The protrusions (41) are provided in a flange (45) at a predetermined distance from the peripheral end (43a) of a cylindrical portion (42) of the first roller (21) in a sheet width direction. The distance from the center of rotation of the flange (45) to the front end (41c) of each of the protrusions (41) is equal to or less than the radius of the cylindrical portion (42).

主权项

1. A sheet ejection device comprising an ejection roller pair including at least one first roller and at least one second roller pressed to contact with each other for ejecting a sheet by a pressure contact portion, wherein
the at least one first roller includes a cylindrical portion pressed to contact with the at least one second roller, and a disk shaped flange formed on the same rotation axis as the cylindrical portion with an interval from a peripheral end of the cylindrical portion in a sheet width direction, the flange is provided with at least one a protrusion protruding in a radial direction from an outer circumference surface of the flange so as to contact with a back end of the sheet to be ejected along with rotation of the at least one first roller, the at least one protrusion includes a sheet pushing surface substantially perpendicular to the outer circumference surface and an inclined surface inclined with respect to the outer circumference surface, and a distance in the radial direction from a center of rotation of the flange to a tip of the at least one protrusion is equal to or smaller than a radius of the cylindrical portion.