Patent ID: 7885587

Claim:
An image forming apparatus for forming an image on a recording member by forming a latent image on a surface of a rotating latent image support, applying a toner on the latent image to form a toner image, and transferring the toner image onto the recording member supported on a surface of a surface moving member, or transferring the toner image onto the surface of the surface moving member and transferring the toner image on the surface of the surface moving member onto the recording member, comprising: a driving control unit configured to drive and control the latent image support so that the latent image support rotates at a target rate; a first detecting unit configured to detect plural detection patterns which are formed by forming latent images on the surface of the latent image support, develop the latent images, and transfer the developed latent images onto the surface of the surface moving member, and are arranged along a surface moving direction of the surface moving member; plural parts to be detected, which revolve in accordance with a rotation of the latent image support; a second detecting unit configured to detect one or more of the parts to be detected passing by a specific point on a movement path of the parts to be detected; a first correcting pattern generating unit configured to obtain a first amplitude and a first phase of a fluctuation component of an interval between the detection patterns, which indicates a periodic fluctuation of a surface moving speed of the latent image support, from pattern detection data obtained by detecting the plural detection patterns by the first detecting unit, and generate a first rate correcting pattern for canceling out the periodic fluctuation of the surface moving speed based on the first amplitude and the first phase; a second correcting pattern generating unit configured to perform an obtaining process to obtain a second amplitude and a second phase of a fluctuation component of an interval between the parts to be detected, which indicates a periodic fluctuation of the surface moving speed of the latent image support, from parts detection data obtained by detecting the plural parts to be detected by the second detecting unit in a predetermined time in which the latent image support rotates once or more, perform the obtaining process again at a predetermined timing to obtain a third amplitude and a third phase, calculate a change amount of the third amplitude and the third phase with respect to the second amplitude and the second phase, and generate a second rate correcting pattern for canceling out the change amount; and a correcting unit configured to correct the target rate by superimposing the first rate correcting pattern and the second rate correcting pattern with the target rate.