Vibration and noise induced by electrostatic force on a contact charger roller of electrophotography

Electromechanical dynamics of a contact charging subsystem of electrophotography were investigated to clarify fundamental characteristics of mechanical vibration and acoustic noise induced by electrostatic force on a contact charger roller. The following conclusions were deduced from modeling and experiments. (1) Alternating electrostatic force is yielded in the vicinity of the nip between the charger roller and a photoreceptor drum because ac voltage applied between the roller and the drum induces a high alternating electrostatic field in the vicinity of the nip. Noise is caused mainly by the resonance vibration of a cartridge cover that contains the roller and the photoreceptor drum. Noise due to gas discharge and pipe resonance of the drum is minor. (2) The main frequency of the electrostatic force is twice that of the ac applied voltage. The magnitude of the electrostatic force is large under high ac applied voltage operation. Therefore the resonant frequency of the cartridge cover should be designed to be significantly different from twice that of the ac voltage frequency, and it is preferable to set the ac voltage as low as possible.