An image forming apparatus for forming an image on a sheet by transferring a color medium from a transfer medium to the sheet in a transfer position in accordance with an image pattern comprises a recording head, a platen, and a pair of pressure rollers for pressing the sheet against the platen. A pair of separating rollers for separating the transfer medium from the sheet are arranged between the transfer position and their corresponding pressure rollers. The platen is coupled to a conveyance control mechanisms for reciprocating the sheet in the transfer position. In operation, the sheet is fed in the forward direction, the color medium of the transfer medium is transferred to the sheet in the transfer position, and then the transfer medium and the sheet are separated by the one separating roller. After the color medium is transferred to the trailing end portion of the sheet, the sheet is fed in the backward direction, and the transfer medium and the trailing end portion of the sheet are separated by the other separating roller.