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Process/Operation > Image Formation System > Controls > Drum Cleaning
Process/Operation > Image Formation System > Controls > Drum Cleaning
● Auxiliary Brush Control
By controlling the polar character of the transfer-residual toner on the surface of the
Photosensitive Drum, attachment of the toner to the Primary Charging Roller is prevented
and also collecting performance of the toner in the Developing Assembly is improved.
Control timing
1) Immediately after the primary transfer
Control description
1) Bias value of the Upstream Brush and the Downstream Brush is determined according
to the environment.
2) The Upstream Brush neutralizes electric charge on the Photosensitive Drum.
3) The Downstream Brush supplementarily makes the Photosensitive Drum negatively-
charged.
4) The negatively-charged residual toner is repelled by the negative bias of the
Developing Cylinder and collected into the Developing Assembly.
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Photosensitive Drum
Developing Cylinder
Upstream Brush
Toner which was not
transferred to ITB
Charge toner positively.
Charge negatively from the positively
charged toner.
Downstream Brush
Primary Charging Roller
F-2-80
● Brush Discharge Control
Toner accumulated with the Auxiliary Brush is discharged to maintain performance of the
Auxiliary Brush.
Control timing
1) At last rotation
2) At power-on
3) At recovery from sleep mode
4) At every 100 sheets (accumulated) during printing
Control description
1) Switching bias of the Upstream Brush or the Downstream Brush (ON/OFF) can
discharge toner (positively/negatively charged respectively) attached with the Brush to
the Photosensitive Drum.
2) The toner discharged from each Brush is transferred to the ITB (primary transfer) and
collected into the ITB Cleaning Unit in the end.
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Residual Toner on the Brush
Upstream Brush
Photosensitive Drum
Downstream Brush
F-2-81
