An image forming apparatus including a control section which detects an offset of a recording sheet being conveyed, the offset being in a main scanning direction perpendicular to a conveyance direction of the recording sheet; performs an offset regulation control which adjusts a main scanning direction image area signal in accordance with the offset; and forms a patch at a non-transfer area on an image carrier, wherein the control section performs a first control based on the offset of the recording sheet for the offset regulation control while a sub scanning direction image area signal is active for image forming on the recording sheet, and performs a second control for the offset regulation control while the image area signal in the sub scanning direction is inactive.