Electrophotographic copier permitting a toner dispensing cassette to be subsequently employed as a residual toner receptacle

In a photocopier including a movable member carrying a photoconductive layer, a charging station for charging the layer, an illuminating station for photographically exposing the layer, a developing station provided with a magnetic brush and arranged to supply a magnetic single component toner to the brush for developing the image formed on the layer, a transfer station for transferring the developed image to a record material sheet, and a cleaning station for cleaning the layer, the stations being disposed in succession along the path of movement of the movable member for bringing each portion of the layer into operative association with each station in succession, in combination with a cassette containing a supply of such toner, the improvement wherein said developing station comprises means for receiving and holding said cassette in a position for dispensing toner for supply thereof to the magnetic brush, said cleaning station comprises means for receiving and holding said cassette in a position for collecting residual toner removed from the photoconductive layer in said cleaning station, whereby one and the same cassette can be used to initially supply toner to said developing station and, after having been emptied, can serve as a receptacle for residual toner in said cleaning station, said cassette has an open state in which a flow passage is present between its interior and the region outside of said cassette and a closed state in which its interior is closed, and said means at said developing and cleaning stations are constructed for permitting said cassette to be inserted in or removed from each said station only when in its closed state.