Charging device, image forming apparatus and image forming method
AssigneeRicoh Company, Ltd.
InventorMakoto Satoh
Life of this patent
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Abstract
A charging device according to an embodiment includes a surface potential sensor configured to output a result of detecting a surface potential of a photoconductor, on which charge is deposited by the charging device, of an image forming apparatus and a main control unit. The main control unit is configured to perform a charging-current determining process which determines a charging-current setpoint value, which is an output setpoint value for constant current control of a charging bias to be fed from a corona power supply, based on a difference between the result of detection output from the surface potential sensor and a grid setpoint value, which is an output setpoint value for constant voltage control of a grid bias to be fed from a grid power supply, at predetermined timing.
Claims7
A charging device comprising:
- a discharge electrode for establishing a discharge;
- a grid electrode arranged between the discharge electrode and a latent-image bearer of an image forming apparatus;
- a charging power supply configured to feed, with constant current control, a charging bias to be applied to the discharge electrode to deposit charge on a surface of the latent-image bearer by establishing the discharge between the discharge electrode and the latent-image bearer;
- a grid power supply configured to feed a grid bias to be applied to the grid electrode with constant voltage control;
- and
- a control unit configured to perform a grid determining process, the grid determining process determining a grid setpoint value, the grid setpoint value being an output setpoint value for the constant voltage control of the grid bias,
- characterized in further comprising a surface potential detector configured to output a result of detecting a surface potential of the latent-image bearer where charge is deposited by the discharge,
- wherein the control unit is configured to perform a charging-current determining process, the charging-current determining process determining a charging-current setpoint value, the charging-current setpoint value being an output setpoint value for the constant current control of the charging bias, based on a difference between the result of detection output from the surface potential detector and the grid setpoint value at predetermined timing.
Dependencies are inferred from the claim text.