An image forming apparatus for performing a printing job using an
intermediate transfer belt is provided. The image forming apparatus has a
voltage determination part for determining a predetermined level of a
refresh charge corresponding to a potential difference which is generated
on opposite surfaces of the intermediate transfer belt, and a power
supply for supplying the refresh charge to the intermediate transfer belt
so that the potential difference is offset. The power supply supplies the
refresh charge to the intermediate transfer belt through a certain roller
which is in contact with the intermediate transfer belt. Accordingly, the
potential difference caused by the polarization in the intermediate
transfer belt is offset by the refresh charge, and the variation of the
resistance caused by the potential difference is prevented.