Patent ID: 8737891

Claim:
A belt driving apparatus comprising: an endless belt stretched around a plurality of rollers; a driving roller that rotationally drives the belt, the driving roller being one of the plurality of rollers; a receiving roller that receives an external force through the belt, the receiving roller being another one of the plurality of rollers; one or more driven rollers rotated by rotation of the belt and arranged in an area that is upstream of the receiving roller and downstream of the driving roller in a rotational direction of the belt, the driven rollers being the remaining ones of the plurality of rollers, at least one of the driven rollers being supported to be movable in radially inward and outward directions of the belt in accordance with a tension in the belt; and a braking unit that performs braking by pressing a frictional member against a rotational shaft of one of the driven rollers and generating a frictional force, the braking unit including a mechanism that converts a displacement of the movably supported driven roller in the radially outward direction of the belt into a relative displacement between the rotational shaft and the frictional member, the displacement of the movably supported driven roller being caused when the external force is applied to the receiving roller so as to decelerate rotation thereof.