Image transfer unit of image formation apparatus

摘要

An image transfer unit of an image formation apparatus is composed of a belt-shaped image bearing member on which a toner image is to be formed, a plurality of supporting and tension-application rollers which supports and provides tension to the belt-shaped image bearing member, an image transfer roller for transferring the toner image from the belt-shaped image bearing member to a transfer sheet, and a backup member having an outer peripheral elastic layer with a predetermined elasticity. The elastic layer of the backup member is urged with a predetermined pressure toward the image transfer roller via the belt-shaped image bearing member, with the belt-shaped image bearing member being held between the elastic layer of the backup member and the image transfer roller.