An image forming apparatus comprises a paper feeding unit which feeds a sheet-shaped recording medium, an image forming unit which forms a toner image on the recording medium fed from the paper feeding unit, a fixing unit which fixes the toner image formed by the image forming unit on the recording medium, a stacking unit which stacks the recording medium on which the toner image is fixed by the fixing unit, a temperature sensor which detects the surface temperature of the recording mediums stacked on the stacking unit and a control unit which determines, according to the printing information of the recording medium, whether or not to feed a new recording medium from the paper feeding unit when the surface temperature of the recording mediums detected by the temperature sensor is above a threshold temperature.