An image forming apparatus includes a control unit to control a latent image support with a target rate; a first unit to detect patterns; plural parts to be detected revolving with the support; a second unit to detect passing of the part; a first generating unit to obtain an amplitude and a phase of fluctuation and a pattern for canceling out the fluctuation from the amplitude and the phase; a second generating unit to perform a process to obtain an amplitude and a phase of fluctuation while the support rotates once or more, perform the process again, calculate a change in the amplitude and phase, and generate another pattern for canceling out the change; and a correcting unit to correct the target rate by superimposing the patterns with the target rate.