An image forming apparatus includes a defect position detecting section to detect a defect position at which no recording material is outputted; a defect position specifying section to specify a defect recording element, which resides at the defect position, and a kind of recording material to be outputted by the defect recording element; a mixture ratio determining section to determine a mixture ratio of plural recording materials, so as to make the mixture ratio of a specific recording material to be outputted by plural recording elements residing in a peripheral area of the defect position and including the defect recording element, decrease to a value lower than a normal mixture ratio, while using the normal mixture ratio for other recording elements residing in other areas.