Patent ID: 6278857
Filing Date: 2001-08-21
Classification: G03G

Abstract:
A color image forming apparatus comprising:a) a plurality of image stations including photosensitive drums and developing unit for developing the latent images formed on said photosensitive drums as toner images,b) a transfer unit for transferring and conveying the toner images formed in said plurality of image stations onto an intermediate transfer material,c) a plurality of exposure units for irradiating the individual photosensitive drums in said plurality of image stations with light for forming latent images,d) a plurality of drive motors for driving said plurality of photosensitive drums independently,e) a plurality of motor rotation controllers for controlling rotation and driving of said plurality of drive motors independently,f) a plurality of rotation phase detectors for detecting the rotation phase of each of said plurality of photosensitive drums rotated and driven by said drive motors,g) a rotation phase difference calculator for calculating the rotation phase difference of other photosensitive drums corresponding to the rotation phase of a specified photosensitive drum as a reference among the rotation phases detected by said plurality of rotation phase detectors,h) a phase correction setting unit for setting said rotation phase difference of said other photosensitive drums in a printing operation, andi) a phase correction controller for correcting rotation phase of said other photosensitive drums on the basis of said calculated rotation phase difference and said set rotation phase difference, wherein said rotation phase is corrected in steps depending on a phase correction amount set for each step.