Patent ID: 8070252

Claim:
An image forming apparatus, comprising: a transport belt configured to transport a recording sheet in a sub-scanning direction; a carriage for mounting a recording head, the carriage configured to be reciprocally moved in a main scanning direction to record an image on the recording sheet; a reflection sensor mounted on the carriage, the reflection sensor configured to receive light reflected from the transport belt to detect a leading edge of the recording sheet and output a detection signal corresponding to the received light; and a control unit, the control unit configured to control a contamination check process in which, when the image forming apparatus is activated and before transporting the recording sheet to the transport belt, the control unit instructs the carriage to move to a given position over the transport belt and to drive the transport belt for one rotation while maintaining the carriage at the given position and determines whether contamination exists on the transport belt based on the detection signal output from the reflection sensor; and a position detector configured to detect a drive position of the transport belt and to detect a position of contamination on the transport belt when contamination on the transport belt is detected.