Patent ID: 7450888

Claim:
A method of detecting a home position error for an image forming apparatus, comprising the steps of turning on an actuator; determining whether a leading end of an indicating unit is sensed by a sensor; determining whether a trailing end of the indicating unit is sensed by the sensor; determining whether a total time taken by the indicating unit to pass through the sensor is substantially identical to a predetermined time taken by at least one of yellow, magenta, cyan and black indicating units to pass through the sensor, each of the yellow, magenta, cyan and black indicating units having a different circumferential length; and displaying a home position error message when the total time taken by the indicating unit to pass through the sensor is not substantially identical to the predetermined time taken by one of the yellow, magenta, cyan and black indicating units to pass through the sensor when determining whether the total time taken by the indicating unit to pass through the sensor is substantially identical to the predetermined time.