Image forming apparatus having control structure for cleaning the transfer device

摘要

A transfer sheet detect sensor for detecting the presence or absence of a transfer sheet is disposed between a point of contact where a developing device for developing an electrostatic latent image formed on an image carrier to form a toner image is contacted with a transfer roller in a transfer portion and a point of tucking provided just upstream of the contact point where the transfer sheet is tucked into the image carrier just upstream of the contact point, the transfer roller is disposed such that it can be contacted with and retreated (separated) from the image carrier, and a cleaning roller is provided such that it can be contacted with the transfer roller while the transfer roller is retreated to its separated position, whereby a given cleaning voltage is applied to the transfer roller when the transfer roller is cleaned by the cleaning roller.