Electrophotographic apparatus having a fringe development preventing mechanism

An electrophotographic apparatus comprising:

• a photosensitive member;
• an exposing device for exposing the photosensitive member to light and charging the photosensitive member to form at least three regions of a high potential region, an intermediate potential region and a low potential region on the photosensitive member;
• a developing device for developing the high potential region and the low potential region respectively using different colored particles by normal development and reversal development;
• and
• an exposing device controller for controlling the exposing device to change the amount of exposing light for each of the three regions,
• wherein the exposing device controller has a laser driver for controlling the exposing device to form a fringe development preventing potential in an edge of at least one of the three regions and to prevent fringe development from occurring therein;
• and
• the laser driver performs pulse-width modulation to control an auxiliary exposure amount at the time of forming the fringe development preventing potential,
• wherein the fringe development preventing potential has two or more potential levels which are changed stepwise or continuously;
• and
• the laser driver performs the pulse-width modulation in accordance with a change of the potential of two or more levels.