Electrostatic copier or printer with DC energised charging roller

摘要

The copier/printer has a charging roller (100) in contact with the photosensitive drum as an alternative to the conventional corona discharge device. The roller (1200) has a 6 mm diameter metallic core (101) connected to a DC source and is covered by an elastic layer (102) 3mm thick of eg epichlorohydrin rubber having a specific resistance of 3x10 power 8 ohm.cm. Another film (103) of similar material treated with a solution of fluorine based resin of 30 micrometres thickness and having a specific resistance of 3x10 power 10 ohm.cm completes the assembly.