Patent ID: 7844206

Claim:
An image forming apparatus, comprising: a plurality of image forming sections for forming a plurality of toner images of different colors; a patch toner image forming section for forming a plurality of patch toner images side-by-side onto a moving transfer body by using the plurality of image forming sections; a spread clock signal output section for spreading a clock signal having a predetermined standard frequency at a predetermined spreading ratio and outputting the clock signal; a patch toner image intervals calculating section for calculating intervals between the patch toner images formed on the transfer body, based on the number of clock signals outputted during a predetermined time interval from the spread clock signal output section and the standard frequency; and a calculation result correcting section for counting the number of spread clock signals outputted from the spread clock signal output section at a predetermined time interval, and correcting a calculation result given by the patch toner image intervals calculating section based on the result of the counting.