Patent ID: 8265493

Claim:
An imaging apparatus, comprising: a housing; a toner cartridge within the housing, the toner cartridge having a rotatable shaft; a cam mounted outside the toner cartridge on the rotatable shaft; an optical sensor mounted on the housing having an emitter and a receiver, the emitter and the receiver forming an optical path, the optical sensor having an output that changes when the optical path changes from blocked to unblocked and from unblocked to blocked; and a flag mounted on the housing having a first arm and a second arm, the flag having a home position where the first arm is disposed in the rotational path of the cam and the second arm is disposed in one of: blocking the optical path and unblocking the optical path; wherein rotation of the rotatable shaft causes the cam to engage and disengage the first arm causing the second arm to change from one of blocking the optical path and unblocking the optical path.