According to an aspect of the invention, an image forming apparatus includes an image correction unit and a determination unit. The image correction unit inserts a new pixel between pixels forming image data with a plurality of pixels printed using a plurality of print color materials arranged in a main scanning direction in order to correct the image width in the main scanning direction. The determination unit determines whether or not the image data is specified for print with a dot representing given information superposed. When the determination unit determines that the image data is specified for print with the dot superposed, a prohibition unit included in the image correction unit prohibits insertion of the new pixel into a pixel string of a print color material of a similar color to the print color material for the dot.