Developing bias power unit for use in an image forming apparatus.

摘要

An image forming apparatus accommodates a developing bias power unit (10) for applying a bias voltage to a developing sleeve (4a) by the use of a DC power source (11) of which an output is on-off controlled. When the output of said DC power source (11) is activated, an electricity storage element (16) interposed between said DC power source (11) and said developing sleeve (4a) is electrically charged by an output voltage of said DC power source (11), and a first voltage is applied to said developing sleeve (4a). In contrast, when the output of said DC power source (11) is deactivated, a second voltage of reverse polarity is applied to said developing sleeve (4a) by electric charge held in said electricity storage element (16). <IMAGE>