An image forming apparatus of the present invention includes a bias power supply
for applying a bias VB to a developer carrier on which a developer is
deposited. A charge potential deposited on an image carrier, which faces the developer
carrier for forming a latent image thereon, is 400 V or below in absolute value.
Assume that the potential of the image carrier is lowered to VL after
exposure, that a development potential is |VB-VL|, that the
maximum set value of the development potential for development is |VB-VL|max,
and that the development potential varies in a range satisfying relations:
Then image density varies by a width of 10% of image density corresponding to
the maximum set value of the development potential or less.
