Patent ID: 7437098

Claim:
An image forming apparatus, comprising: a plurality of image bearing bodies arranged in a predetermined sequence, each having a point of contact on an intermediate transfer medium; and a plurality of supporting rollers for driving the intermediate transfer medium, wherein a distance between respective points of contact along a running direction of the intermediate transfer medium of at least two image bearing bodies is a positive integer multiple of a length of a circumference of at least one of said supporting rollers; wherein at least two image bearing bodies have a radius deviation in which the radius varies along the direction of circumference, and have respective intervals A 1 and A 2 having a predetermined location of maximum radial displacement, and are mounted to satisfy: {2 π·l+(α 2−α1)}·Ro=L1, ( l =0, 1, 2, . . . ),(Ro=Ro1=Ro2) where α 1 is the angle, which is measured from the transfer starting location of the first image bearing body to the center of the interval A 1 , in the direction of reverse rotation of the first image bearing bodies; α 2 is the angle, which is measured from the transfer starting location of the second image bearing body to the center of the interval A 2 , in the direction of reverse rotation of the second image bearing bodies; and Ro 1 and Ro 2 are radii of the respective image bearing bodies.