Image forming apparatus

An image-forming apparatus including a cleaning means (6) for selectively removing foreign matters other than developer remaining on the surface of a photoconductor drum (1) therefrom after a transferring process. The cleaning means (6) is provided with a foreign-matter removing roller (11) which comes into contact with the surface of the photoconductor drum (1). Foreign matters, which are charged by a transferring device (5) to have a polarity reversed to that of the charged electric potential of toner through an electric field that is exerted between the surfaces of the roller (6) and the photoconductor drum (1), are allowed to adhere to the surface of the foreign-matter removing roller (6). As for the surface of the foreign-matter removing roller (6), the surface electric potential of the foreign-matter removing roller (6) is biased further toward the polarity of the charged toner than the surface electric potential of the photoconductor drum (1) at the contact portion between the photoconductor drum (1) and the foreign-matter removing roller (6). Thus, it becomes possible to provide an image forming apparatus which is capable of supplying images with good picture quality for a long time, by using a cleaning operation of this cleaning means.