An image forming apparatus and method to operatively control the same. The apparatus includes an ink cartridge having a plurality of print heads arranged in a widthwise direction of a print medium, a wiping unit to wipe the print heads while moving in the print medium feeding direction, a positional information providing unit to provide positional information about a position of the wiping unit, and a controller to operatively control the print heads. The controller controls the print heads that, on the basis of the positional information provided and offset information of the ink cartridge, the controller estimates a wiping timing to wipe the nozzles of the print heads with the wiping unit and determines a spitting timing to eject a predetermined amount of ink in the wiped sequence of the nozzles, whereby that the wiping and spitting operations are performed at the estimated wiping timing and the determined spitting timing.