Abstract: An image forming apparatus includes a power supply, a detection member, a plurality of band-pass filters, and a setting unit. The power supply outputs a first charging bias having a first frequency or a second charging bias having a second frequency that is an integral submultiple of the first frequency. The detection member detects a current flowing through a charging member. Each of the plurality of band-pass filters receives an output of a current detected by the detection member. The setting unit uses the band-pass filters for both setting of a peak-to-peak voltage of the first charging bias and setting of a peak-to-peak voltage of the second charging bias.

Abstract: When ending image forming, a state is realized where charging by a charging roller is stopped (charging bias off) and also applying DC voltage at a developing device is stopped (developing bias DC off). In this state, AC voltage is applied to the developing device (developing bias AC on), thereby adhering toner to the surface of a photosensitive drum and forming interposing toner. Driving of the photosensitive drum and an intermediate transfer belt is then stopped in the state with the interposing toner interposed between the photosensitive drum and intermediate transfer belt.

Abstract: An image forming apparatus includes a power supply, a detection member, a plurality of band-pass filters, and a setting unit. The power supply outputs a first charging bias having a first frequency or a second charging bias having a second frequency that is an integral submultiple of the first frequency. The detection member detects a current flowing through a charging member. Each of the plurality of band-pass filters receives an output of a current detected by the detection member. The setting unit uses the band-pass filters for both setting of a peak-to-peak voltage of the first charging bias and setting of a peak-to-peak voltage of the second charging bias.

Abstract: When ending image forming, a state is realized where charging by a charging roller is stopped (charging bias off) and also applying DC voltage at a developing device is stopped (developing bias DC off). In this state, AC voltage is applied to the developing device (developing bias AC on), thereby adhering toner to the surface of a photosensitive drum and forming interposing toner. Driving of the photosensitive drum and an intermediate transfer belt is then stopped in the state with the interposing toner interposed between the photosensitive drum and intermediate transfer belt.

Abstract: An image forming apparatus includes a photosensitive member; a charging member contactable to said photosensitive member to electrically charge said photosensitive member; applying means applying a charging bias voltage to said charging member; detecting means detecting a current flowing between said charging member and said photosensitive member; a controller for controlling said image forming apparatus to execute an operational mode for removing an electric discharge product deposited on a surface of said photosensitive member, in the case that detecting means detects a current not lower than a predetermined value when a voltage lower than a voltage at which an electric charge starts between said photosensitive member and said charging member is applied to said charging member.

Abstract: An image forming apparatus includes a photosensitive member; a charging member contactable to said photosensitive member to electrically charge said photosensitive member; applying means applying a charging bias voltage to said charging member; detecting means detecting a current flowing between said charging member and said photosensitive member; a controller for controlling said image forming apparatus to execute an operational mode for removing an electric discharge product deposited on a surface of said photosensitive member, in the case that detecting means detects a current not lower than a predetermined value when a voltage lower than a voltage at which an electric charge starts between said photosensitive member and said charging member is applied to said charging member.