Image forming apparatus that detects presence of sheet on transport route, and posture of branch guide, with single sensor

An image forming apparatus comprising:

• an image forming device that forms an image on a sheet;
• a fixing device that fixes the image onto the sheet;
• a first transport route extending from the fixing device to a delivery port;
• a second transport route branched from the first transport route, and extending toward the image forming device;
• a branch guide that assumes a first guide posture, to guide the sheet to the first transport route, and assumes a second guide posture, to guide the sheet to the second transport route;
• a sheet contact member that assumes a non-contact posture, when not in contact with the sheet on the first transport route, and assumes a contacting posture, when in contact with the sheet on the first transport route;
• a detection object that assumes a first detection posture, when the branch guide assumes the first guide posture and the sheet contact member assumes the non-contact posture, and assumes a second detection posture, when the branch guide assumes the second guide posture, or when the branch guide assumes the first guide posture and the sheet contact member assumes the contacting posture;
• and
• a sensor that outputs a first signal, when the detection object is in the first detection posture, and outputs a second signal, when the detection object is in the second detection posture.