Patent ID: 8422903

Claim:
An image forming apparatus comprising: a pattern forming unit that forms a pattern for correcting a position shift of an image; a detecting unit that detects the pattern; a measuring unit that measures a first time from a start of a control signal for controlling timing to start forming the image until a detection of the pattern; and a control unit that controls position-shift corrections of a position of forming the image based on the time measured by the measuring unit and a reference time, wherein for a first position-shift correction, the control unit compares the first time measured by the measuring unit with the reference time and controls a position of forming the image based on a difference between the first time and the reference time, the reference time being the time at which the image position is aligned, and for subsequent position-shift corrections, the control unit sets the reference time as a time measured immediately after a previous position-shift correction, and controls the position of forming the image based on the difference between a first time measured by the measuring unit corresponding to the previous position-shift correction and the reference time.