Patent ID: 7483661

Claim:
An image forming apparatus comprising: a first image bearing member; first toner image forming means, which forms a first toner image on the first image bearing member; a second image bearing member; second toner image forming means, which forms a second toner image on the second image bearing member; an intermediate transfer belt which rotates, wherein a thickness of said intermediate transfer belt periodically varies in a rotation direction of said intermediate transfer belt; a first primary transfer region in which the first toner image on the first image bearing member is transferred to the intermediate transfer belt; a second primary transfer region in which the toner image on the second image bearing member is transferred to the intermediate transfer belt to which the first toner image is transferred, wherein a distance between the central position of the first primary transfer region in the rotating direction of the intermediate transfer belt and the central position of the second primary transfer region is approximately integer multiples of the periodical length of the thickness variation of said intermediate transfer belt in the rotating direction.