Abstract: In a copying machine having a movable carriage 5 for carrying the original, the correct velocity ratio between the carriage and the drive shaft 18 which advances the photosensitive sheet 21 (or photosensitive drum) is established by driving the carriage from a shaft 25 at overspeed through a friction clutch 38 and limiting the carriage velocity to the correct value by a coupling (rack 32, gears 40,43, one-way clutch 29) between the carriage 5 and the drive shaft 18. The correct velocity is thereby maintained irrespective of wear and tolerances in the drive to the carriage and the carriage guides.

Abstract: A magnetic brush developing unit for an electrophotographic copy-machine of the type having a magnetic applicator which moves toner particles along a path passing adjacent the photoconductive element having the latent electrostatic image to be developed, in which a grid having a fine mesh is interposed in this path for separating clots of toner from the toner particles. The clots entrapped in the mesh are vibrated by the magnetic applicator till they are shattered and pass through the mesh.

Abstract: Disposable toner cartridge for copying machine which has an outer casing with a first opening, and a container mounted within the casing and provided with a second opening. The container is movable between a position of containment of the toner, in which it is maintained during shipment, and a position of discharge, in which it is turned upon positioning of the cartridge in the copying machine and in which the first and second openings are aligned for discharging therethrough the toner into the copying machine. The casing is provided with clamping elements for clamping the container in the discharge position to prevent any subsequent movement of the container starting from the discharge position, so avoiding the re-use of the cartridge.