Patent ID: 8744313

Claim:
An image forming apparatus driving unit comprising: a rotatable member which is rotatably supported; a pair of bearing portions for rotatably supporting said rotatable member; a motor for driving said rotatable member; a driving gear provided on a driving shaft of said motor; and a driven gear, provided outside said pair of bearing portions with respect to a rotational axis direction of said rotatable member, for engaging with said driving gear to be rotated integrally with said rotatable member, wherein at least one of said driven gear and said driving gear has, with respect to the rotational axis direction of said rotatable member, a crown shape so that a central tooth surface of a tooth projects more than end tooth surfaces of the tooth at a side where said driven gear and said driving gear engage each other, and wherein during driving of said driving gear, a first position where a pressure received by the tooth surface is at a maximum and a second position where an amount of crowning formed on said driven gear or said driving gear is at a maximum are offset in a same direction.