Patent ID: 8191885

Claim:
A method of detecting a home position of a moving member by detecting a part of the moving member using a detecting unit, the method comprising: setting in advance a detection range within which the home position can be recognized; setting, when the detecting unit detects a part to detect the home position of the moving member in a state in which the moving member is stopped, a detection position as the home position by assuming that the detection position is in the detection range without operating the moving member once to move the moving unit out of a detection range of the detecting unit, the home position being performed immediately after stopping or before starting a sheet feeding or a sheet processing; controlling, when performing homing operations of processing units to return the processing units to respective home positions, a processing unit for which a non-home-position state is detected to perform the homing operation, excluding a processing unit for which a home position state is detected; and detecting an abnormal state of each of the processing units, wherein upon detecting an abnormality of any one of the processing units, storing information on the abnormality in an abnormality-information storing unit, and when performing the homing operations of the processing units, determining whether to perform the homing operation of a processing unit from which the abnormality is detected, based on the information stored in the abnormality-information storing unit.