A heat fixing apparatus for fixing an unfixed image formed on a recording material
is provided with a discharge roller coming into contact with a recording material
and positioned at a downstream side of a fixing nip in a conveying direction of
the recording material, and, for improving a fixed image tailing phenomenon, applies
a bias voltage to at least either of a fixing film and the discharge roller. In
case the recording materials are fed in continuous manner, a bias voltage while
the recording material is passed through the fixing nip is elevated or lowered
according to a number of heating of the recording materials. In this manner it
is possible to reduce deposition of toner, paper powder, dust etc. to the surface
of the fixing member, generated particularly in case of a continuous supply of
the recording materials under a high bias voltage, thereby preventing generation
of an image defect such as blobs resulting from a toner contamination.
