Patent attributes
An image forming apparatus includes: a plurality of image forming units as defined herein; an image carrier as defined herein; a first operation controlling unit as defined herein; a second operation controlling unit as defined herein; a density detecting sensor that detects densities of the images formed on the image carrier; a measuring unit that binarizes a density detection output of the image position deviation correction patterns formed on the image carrier, from the density detecting sensor, and that measures intervals between color patterns of the image position deviation correction patterns, based on the binarized output; and a position deviation correction controlling unit that performs a position deviation correcting control of, when the intervals measured by the measuring unit and of the color patterns in the image position deviation correction patterns are deviated from a predetermined range, correcting position deviation of the toner images formed by the image forming units.