Canon imageRUNNER ADVANCE C350 series Service Manual page 95

2
Technical Explanation > Laser Exposure System > Various Controls > Dustproof shutter control
■ BD correction control
● Purpose
This is to correct the displacement of writing start position of each color laser due to the angle
variation of Polygon Mirror facet.
● Execution timing
At power-ON, per printing
● Control detail
1) The DC Controller measures the BD interval after the completion of constant speed rotation
control of the Scanner Motor.
2) The DC Controller calculates the correction value from the offset of the BD interval.
3) The write start position is corrected by correcting the write start timing based on the above
correction value.
START
Scanner motor control finish
(Constant-speed
rotation detection)
Specified
value
BD interval measurement
Before
correction
Write start position
correction value calculation
Write start position
After
correction value
correction
END
2 Technical Explanation > Laser Exposure System > Various Controls > Dustproof shutter control
BD interval
BD1 BD2
Gap Gap
BD1 BD2
Gap Gap
BD1 BD2
F-2-67
■ Dustproof shutter control
● Purpose
This is to prevent the residue toner from sticking to the dust-prevention glass. Or to prevent
the laser light from emitting to the machine inside when the front cover / right cover is opened.
● Execution timing
At image formation and when the Waste Toner Container is removed and then installed.
● Control detail
The Waste Toner Container and the Shutter Lever of the Laser Scanner Assembly operate in
conjunction with each other to open/close the Dustproof Shutter.
When the Waste Toner Container is inserted, the Dustproof Shutter opens, and when the
Waster Toner Container is removed, the Dustproof Shutter closes.
Dustproof Shutter
Shutter Lever
2-52
Waste Toner Container
F-2-68
2-52