Patent ID: 8165502

Claim:
A belt driving controller, which controls driving of a belt that is wound around a plurality of sustaining rotation bodies including a driven sustaining rotation body that is rotated together with a movement of the belt and a driving sustaining rotation body that transmits a driving force to the belt, comprising: a control unit, which controls the driving of the belt so that a moving velocity fluctuation of the belt caused by a pitch line distance fluctuation in the belt circumference direction becomes small, based on rotation information of rotation angle displacements or rotation angle velocities in two of the sustaining rotation bodies, in which two sustaining rotation bodies the diameters thereof are different from each other and/or the degrees to which the pitch line distances of parts of the belt which parts wind around the two sustaining rotation bodies influence a relationship between the belt moving velocity and the rotation angle velocities of the two sustaining rotation bodies are different from each other; wherein the control unit controls a process, where one value corresponding to a certain parameter in two pieces of rotation fluctuation information whose phases are different and which information is included in the rotation information of the two sustaining rotation bodies is greater than the other value corresponding to the same parameter in the two pieces of the rotation fluctuation information, by obtaining the two pieces of the rotation fluctuation information, and controls the driving of the belt by using a result of the process.