| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of avoiding deterioration of accuracy in a positional displacement correction and phase adjustment caused by forming an image for detecting positional displacement and an image for detecting speed variation in such a state that a linear velocity difference is provided to photoreceptors 3Y, 3C, 3M and 3K. <P>SOLUTION: The image for detecting positional displacement and the image for detecting speed variation are formed in such a state that the photoreceptors 3Y, 3C, 3M and 3K are driven at the same linear velocity as one another by a positional displacement correction control where toner images formed on the photoreceptors 3Y, 3C, 3M and 3K are transferred to an intermediate transfer belt 41 so as to form the image for detecting positional displacement, and the positional displacement of each toner image is restrained by setting the drive speed of the photoreceptors 3Y, 3C, 3M and 3K respectively individually on the basis of a result obtained by detecting the image for detecting positional displacement by an optical sensor unit 136, and a variation pattern detection control where the image for detecting speed variation comprising a plurality of toner images is formed on the photoreceptors 3Y, 3C, 3M and 3K and transferred to the intermediate transfer belt 41, and a speed variation pattern per rotation of the photoreceptor is detected on the basis of a result obtained by detecting the image for detecting speed variation by the optical sensor unit. <P>COPYRIGHT: (C)2008,JPO&INPIT |
