IMAGE CONTROLLER

PROBLEM TO BE SOLVED: To control belt moving speed more accurately by eliminating an error caused by the uneven thickness of a belt and the eccentricity of a roller shaft which have been superposed on the measured belt moving speed. SOLUTION: An image controller includes a speed ratio operating section 401 which has a laser Doppler velocimeter 311 and a following side encoder 310 which detect the moving speed of a conveyance belt 160 and the rotational angular rate of a following roller while extracting belt profile data and roller profile data from the measured speed ratio, and a correction control section 331 which controls the timing of each image formation with a head unit 110 so that positional deviation between a plurality of images arising on the conveyance belt 160 may become small based on each profile data. These profiles are formed by performing Fourier transform, eliminating a predetermined frequency from the result from the Fourier transform so as to be an effective degree according to the characteristics of the roller, and then performing inverse Fourier transform. COPYRIGHT: (C)2011,JPO&INPIT