Patent ID: 7016642

Claim:
An image forming apparatus comprising: an image forming unit that forms an image on a sheet; a sheet reading unit that detects an end portion of the sheet and a position of a predetermined image formed on the sheet, said sheet reading unit being arranged upstream of said image forming unit, with respect to a sheet convey direction; and a controller that controls timing of said image forming unit to start image forming according to a detection result by said sheet reading unit, wherein said controller controls said image forming unit to form the predetermined image according to a detection of the end portion of the sheet by said sheet reading unit, and, after forming of the predetermined image, the sheet is re-conveyed to said image forming unit, and wherein said controller calculates a correction value for the timing according to the detection of the position of the predetermined image by said sheet reading unit and controls the timing according to the correction value to control a position of an image to be formed on the sheet.