Patent ID: 8081904

Claim:
A belt drive control unit for controlling a rotation movement of a belt extendedly supported by a first rotatable device and a second rotatable device, the first rotatable device used as a drive-type rotatable device to support and rotate the belt, the drive-type rotatable device driven by a driver, the second rotatable device used as a driven-type rotatable device, the second rotatable device rotatable when the belt rotates, a rotation of the drive-type rotatable device being detected by a first detector as a first detection result, a rotation of the driven-type rotatable device being detected by a second detector as a second detection result, the rotation of the drive-type rotatable device being controlled in connection with thickness fluctuation in the belt at the driven-type rotatable device using the first detection result and the second detection result, the belt drive control unit comprising; a sampling data acquisition unit to obtain sampling data by sampling a difference value between the first detection result and the second detection result; a correction value generation unit to generate correction value data for each number of rotations of the belt based on the sampling data, the correction value data being used to correct a rotation of the drive-type rotatable device; a correction value storage device to store the correction value data; and a correction value reading control unit to read the correction value data stored in the correction value storage device at a timing determined by number of rotations of the belt for controlling a rotation of the drive-type rotatable device, wherein: the correction value storage device includes a first correction value storage device and a second correction value storage device to store correction value data, the belt drive control unit further comprises a correction value storage control unit to store the correction value data generated by the correction value generation unit to the first and second correction value storage devices alternately based on number of rotations of the belt; and the correction value reading control unit reads the correction value data stored in the first and the second correction value storage devices alternately according to number of rotations of the belt to control a rotation of the drive-type rotatable device.