CONTACT TYPE ELECTRIFYING DEVICE AND IMAGE FORMING DEVICE

摘要

PURPOSE:To carry out sufficient electrification and to generate vibrating voltage which is appropriate for environmental change by controlling vibrating component of the impressed vibrating voltage against an electrifying member to be constant energy. CONSTITUTION:A primary electrification process of a photosensitive body 1 is carried out by having a specified voltage impressed from an electric power source 3 including the constant energy control circuit 30 against a core metal 21 of an electrifying roll 2. At this time, vibrating voltage which is DC offsetting voltage equivalent to a target surface potential (electrifying potential) of the photosensitive body 1 superposed by AC sine wave which is controlled to be the constant energy by a constant energy control circuit 30 is impressed by the electric power source 3. The vibrating component for the impressed vibrating voltage against the electrifying roll 2 is controlled to be the constant energy regardless of load impedance of the electrifying roll 2 by the constant energy control circuit 30. Thus, sufficient electrification can be carried out even in an environment of low temperature and low humidity or when the electrifying roll 2 with a high impedance is utilized. Furthermore, the AC voltage appropriate for displacement of impedance of the electrifying roll 2 due to the environmental change can be generated.