Patent ID: 7277670

Claim:
An image forming apparatus comprising: an image forming unit for forming an image on one side of a recording medium; a transport unit for transporting the recording medium through the image forming unit at an image forming transport speed; a sensor for sensing the type of recording medium transported by the transport unit; a return unit for receiving the recording medium from the image forming unit, transporting the recording medium on a return path that reverses the orientation of the recording medium, and feeding the recording medium into the image forming unit again, so that the image forming unit can form an image on another side of the recording medium; and a control unit for setting different transport speeds for different types of recording media on at least part of the return path, according to the type of recording medium sensed by the sensor while the recording medium is being transported by the transport unit, and controlling the return unit so that the different types of recording media are transported at the different speeds, wherein the control unit keeps the image forming transport speed constant, and controls the return unit so that the recording medium is transported on at least part of the return path at a speed differing from the image forming transport speed; and a media thickness sensor for sensing thickness of the recording medium, wherein the control unit sets the transport speed on said at least part of the return path according to the sensed thickness of the recording medium.