An image forming apparatus and method are provided. The image forming apparatus includes a communication interface unit that receives printing data, an image forming unit that performs an ordinary printing to form an image on printing paper based on the printing data, a paper supplying unit that provides the printing paper to the image forming unit along with a paper supplying route, a determination unit that determines whether a functional printing may be performed on the paper supplying route in an interval section between sheets of the printing paper, and a controller that controls the image forming unit to perform a functional printing, wherein the ordinary printing is a printing performed on one or more sheets of printing paper, and the functional printing is a printing performed in an interval section between the sheets of printing paper.