An image forming apparatus that forms images on sheets by using input image data, the apparatus including: a detection unit that detects a blank area outside of an image forming area formed on a sheet; a setting unit that, when a sum of a length in a conveyance direction of a blank area on a trailing edge side in the conveyance direction of a sheet and a length in the conveyance direction of a blank area on a leading edge side in the conveyance direction of a sheet conveyed following the sheet is a reference value or less, sets a sheet conveyance interval to the reference value, and when the sum is greater than the reference value, sets the conveyance interval to be less than the reference value; and a conveying unit that conveys the sheets at the conveyance interval set by the setting unit.