A module adapted to be mounted removably in a printing machine. The module has a photoconductive belt entrained about a plurality of rollers mounted on a frame. One of the rollers is movable between a non-operative position, in which the space between the rollers is reduced, and an operative position, in which the space between the rollers is increased. A charging station and a cleaning station are mounted on the frame of the module adjacent the photoconductive belt. When one of the rollers is in the non-operative position, a cover covers at least the photoconductive belt. The cover has an insert about which a portion of the photoconductive is wrapped. The insert supports the photoconductive belt in a non-tensioned condition external to the printing machine.