Chatter vibration of a cleaner blade charged by a contact charger roller was mathematically investigated. From the results of the investigation, the following points were deduced: (1) The chatter vibration is basically induced by nonlinear negative damping due to negative speed dependence of the friction coefficient between the cleaner blade and a photoreceptor drum. Parametric excitation and forced vibration are also generated by the photoreceptor vibration induced by the alternating electrostatic force of the charger roller. (2) Calculated results based on the present model qualitatively agreed with experimental observations, and several methods to suppress the chatter vibration were proposed.