Patent ID: 7821526

Claim:
An image forming apparatus comprising: an image carrier; a scanning unit including a rotating polygonal mirror and configured to perform beam scanning using the rotating polygonal mirror to form an image on the image carrier; a control unit configured to change a rotation speed of the rotating polygonal mirror of the scanning unit to change a magnification of an image to be formed on the image carrier; a carrying member; and an adjustment unit configured to form a patch image in an area on the carrying member between a first area to which an image formed at a first scanning speed is transferred and a second area to which an image formed at a second scanning speed different from the first scanning speed is transferred and to perform an operation for adjusting an image to be formed on the image carrier based on a result of detection of the formed patch image, wherein the adjustment unit is configured to form the patch image after the control unit changes the rotation speed of the rotating polygonal mirror from the first scanning speed to the second scanning speed.