An image forming apparatus includes a plurality of optical scanning units to scan light modulated according to an image signal, a plurality of photoconductive drums to form a plurality of electrostatic latent images by the light scanned from the plurality of optical scanning units, a plurality of developing units to develop the plurality of electrostatic latent images formed on the plurality of photoconductive drums into a plurality of toner images, an intermediate transfer unit to transfer the plurality of toner images developed by the plurality of developing units, a plurality of first transfer rollers installed in the intermediate transfer unit to correspond to the plurality of photoconductive drums, respectively, and to apply transfer voltages that is used to transfer the plurality of toner images onto the intermediate transfer unit, a second transfer roller to transfer the plurality of toner images formed on the intermediate transfer unit onto a paper, and a fixing unit to fix the plurality of toner images transferred onto the paper, wherein the plurality of first transfer rollers includes the first transfer rollers of a first group in which distances between the first transfer rollers of the first group and the plurality of photoconductive drums, respectively, are sequentially reduced downstream along a direction that the intermediate transfer unit travels, and the first transfer roller of a second group is independent from the distances between the first transfer rollers of the first group and the plurality of photoconductive drums.