Abstract: In an image forming apparatus having a reverse development system and using a two-component developer, respective potentials applied when charging an image bearing member and when applying a development bias to a developer bearing member are attenuated when the image bearing member is driven for an operation other than an image forming operation, compared to respective level of potentials applied when the image bearing member is driven for the image forming operation. Thus, an occurrence of an adhesion of a carrier to an image bearing member is reduced to produce a high quality image, when a power switch of the apparatus is turned off or when a door of the apparatus is opened while the image bearing member is driven for an operation other than the image forming operation, or when the apparatus is activated again after the power switch is turned off.

Abstract: A developing device includes a developer bearing member including an internal magnetic field generating device and configured such that a surface thereof moves to carry and convey a developer including toner and carrier. A developer regulating member regulates a quantity of the developer carried and conveyed by the developer bearing member toward a developing area, and a developer accommodating unit accommodates the developer regulated to be conveyed toward the developing area by the developer regulating member. A toner accommodating unit includes a toner supplying opening opposing a surface of the developer bearing surface of the developer bearing member at a position adjacent to and upstream of the developer accommodating unit in a developer conveying direction.