Patent ID: 7085525

Claim:
An image forming unit comprising: an image bearing body, on which a latent image is formed; an intermediate transfer belt, onto which a toner image obtained by developing the latent image formed on the image bearing body is transferred; a primary transfer member for transferring the toner image onto the intermediate transfer belt; a plurality of rolls, across which the intermediate transfer belt is stretched, for applying tension to the intermediate transfer belt; a secondary transfer backup roll, which is one of the plurality of rolls, for backing up secondary transfer by a secondary transfer roll; and a pair of side frames for pivotally supporting the primary transfer member and the plurality of rolls, wherein a positioner, with which a contact member rotatably fitted at both ends of a shaft of the secondary transfer roll is brought into contact, is formed at each side frame in the vicinity of the secondary transfer backup roll, and the positioner is formed in such a manner that an angle formed by each of marginal edges of the positioner in contact with the contact member and a virtual line connecting the center of the shaft of the secondary transfer backup roll to the center of the shaft of the secondary transfer roll becomes acute, as viewed sideways.