Patent ID: 8639140
Filing Date: 2014-01-28
Classification: G03G

Abstract:
1. An image forming apparatus comprising: a plurality of first photosensitive members; a plurality of first chargers provided to correspond to the plurality of first photosensitive members, respectively, wherein each of the plurality of first chargers is configured to charge a corresponding first photosensitive member by corona discharge currents; a plurality of developer carriers provided to correspond to the plurality of first photosensitive members, respectively, wherein each of the plurality of developer carriers is configured to supply developer to a corresponding first photosensitive member; a first charging-bias applying unit connected to the plurality of first chargers, wherein the first charging-bias applying unit is configured to apply charging biases to the plurality of first chargers; a plurality of development-bias applying units provided to correspond to the plurality of developer carriers, respectively, wherein each of the plurality of development-bias applying units is configured to apply development biases to a corresponding developer carrier; a charging-current sensing unit configured to separately sense a charging current flowing in each of the first chargers; and a control unit configured to control the development biases based on the sensed result of the charging-current sensing unit, wherein, in a case where a difference between a reference charging-current value and a detected charging-current value of a charger detected by the charging-current detecting unit exceeds a predetermined value, if the detected charging-current value is larger than the reference charging-current value, the control unit increases an absolute value of a development bias to be applied to a developer carrier corresponding to the charger having the difference exceeding the predetermined value.