Patent ID: 8750779

Claim:
An image forming apparatus, comprising: a main body having a discharge tray provided at a front portion of the main body; a print unit to perform a printing operation on a printing medium, the print unit including a plurality of developing devices, a transfer belt arranged between the plurality of developing devices and a front panel of the main body, and a fixing device; a first discharge roller to feed the printed printing medium fed from the print unit; a reverse roller to reverse a moving direction of the printed printing medium fed from the first discharge roller; a swing roller to swing upward to interact with the reverse roller; a second discharge roller to discharge the printed printing medium fed from the reverse roller to the discharge tray of the main body; a duplex-print circulation path provided between the transfer belt and the front panel of the main body to feed the printing medium to the print unit; and a sensor provided between the fixing device of the print unit and the reverse roller to sense a portion of the printing medium, wherein, in a duplex printing mode, after a printing operation is performed on a first side of a printing medium and a moving direction of the printing medium engaged by the reverse roller is reversed, the reversed printing medium is fed to the duplex-print circulation path to perform a printing operation on a second side of the printing medium, and wherein, in the duplex printing mode, after the printing operation is performed on the second side of the printing medium, the printing medium is fed by the first discharge roller to the reverse roller, and a moving direction of the printing medium is reversed by the reverse roller, the reversed printing medium is discharged to the discharge tray via the second discharge roller, wherein, in the duplex printing mode, when a predetermined time elapses after the sensor senses the portion of the printing medium, the moving direction of the printing medium is reversed by the reverse roller.