Abstract: In a relatively simple copier lacking a discharging unit which erases those portions of a photoconductive element which precede and follow an image, a control device reduces the amount of toner consumed and the amount of toner collected while preventing toner from being scattered around. For a surface portion of the photoconductive element which is associated with a trailing edge portion of a paper to which the image is to be transferred, a charging operation of a charger adapted to charge the photoconductive drum and a charging operation of a transfer charger are stopped. A bias voltage to be applied to a surface portion of the photoconductive element which follows the above-mentioned surface portion is increased.

Abstract: A device installed in a copier, facsimile apparatus or similar image forming apparatus of the type including a fixing unit displays a waiting time necessary for the warm-up of the apparatus. The device calculates an elevation rate of fixing temperature within a predetermined time interval, produces a difference between a current temperature of the fixing unit and a set fixing temperature on the basis of the elevation rate, and thereby determines a waiting time. Further, the waiting time is determined on the basis of a temperature inside the apparatus when the ambient temperature is comparatively low and on the basis of a temperature of the fixing unit when it is higher than a predetermined level.