Patent ID: 8452224

Claim:
A sheet conveyance apparatus comprising: a sheet conveyance roller pair, including an upper roller and a lower roller being urged to the upper roller by an elastic member, wherein the sheet conveyance roller pair conveys a sheet by nipping the sheet with the upper roller and the lower roller, and the position of the lower roller is changed according to a thickness of a sheet being conveyed by the sheet conveyance roller pair against an urging force of the elastic member; an upper sheet guide plate and a lower sheet guide plate provided at a position on the downstream from the sheet conveyance roller pair in a sheet conveyance direction, wherein the upper sheet guide plate and the lower sheet guide plate form a sheet conveyance path therebetween; a sheet guide rib provided on the downstream from the sheet conveyance roller pair in the sheet conveyance direction, wherein the sheet guide rib contacts the lower surface of the sheet conveyed by the sheet conveyance roller pair and can upwardly project into the sheet conveyance path from the lower sheet guide plate and the projecting amount thereof can be changed; a lever provided with the sheet guide rib, wherein the lever extends along the sheet conveying direction; and a shaft which rotatably supports the lever and is provided on the upstream from a rotational center of the lower roller in the sheet conveyance direction, wherein the lever is engaged with the lower roller to rotate around the shaft in conjunction with the changing position of the lower roller such that the more thick a sheet nipped by the sheet conveyance roller pair is, the smaller the projecting amount of the sheet guide rib into the sheet conveyance path becomes.