Bd Correction Control - Canon imageRUNNER ADVANCE C3325 Series Service Manual

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Technical Explanation > Laser Exposure System > Controls > BD correction control

■ BD correction control

● Purpose
Corrects the displacement of each color's laser write start position due to the varied angle of
the Polygon Mirror surface.
● Execution timing
At power-on, and at each print
● Control description
1) The Main Controller PCB measures the BD interval after the completion of constant speed
rotation control of the Scanner Motor.
2) The Main Controller PCB calculates the correction value from the displacement 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 > Controls > BD correction control
BD interval
BD1 BD2
Gap Gap
BD1 BD2
Gap Gap
BD1 BD2
F-2-44
Related Error Code:
E100-0001: BD error
The BD lock was unlocked although it had been locked once.
E110-0001: Scanner Motor error
At startup, the speed was not locked by FG control.
E110-0002: Scanner Motor error
At startup, the speed was not locked by BD control.
E110-0003: Scanner Motor error
At startup, the phase was not locked by BD control.
E110-0004: Scanner Motor error
The laser exposure timing correction of the Polygon Mirror was not detected after phase
lock by BD control.
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