Transfer device and image formation apparatus

摘要

A transfer device comprises a cleaning roller that has a dielectric layer on its surface and cleans the surface of a transfer belt, and transfers a toner image formed on a photosensitive drum onto transfer paper on the transfer belt. A power supply, which applies a cleaning bias of the opposite polarity to an electric charge polarity of the toner that forms a toner image, is provided, and volume resistivity of the dielectric layer is set to 1E3 ohm-cm or more. By specifying characteristic values of the dielectric layer provided on the surface of the cleaning member, the cleaning effect of the dielectric layer can be maintained higher than a predetermined level and the transfer belt can effectively be cleaned.