Canon imageRUNNER ADVANCE C5051 Series Service Manual page 74

2
Technology■>■Laser■Exposure■System■>■Various■Controls■>■BD■correction■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■scanner■mirror■facet.
● Execution timing
■
At■power-ON,■per■printing
● Execution time ■
Within■approx.■0.5s■or■less
● Control detail ■
1)■DC■Controller■measures■the■BD■interval■after■the■constant-speed■rotation■control■of■
Scanner■Motor■is■completed.
2)■DC■Controller■calculates■the■correction■value■according■to■the■gap■of■BD■interval.
3)■Based■on■the■foregoing■correction■value,■image■writing■position■is■corrected.
2 Technology■>■Laser■Exposure■System■>■Various■Controls■>■BD■correction■control
START
Scanner motor
control finish
(Constant-speed
rotation detection)
BD interval
measurement
Constant interval
Narrow interval
BD1 BD2
Writing start correction
value calculation
α
BD1 BD2
Writing start position
correction
α
VDO
BD1 BD2
END
2-38
Constant interval
Constant interval
BD3 BD4
BD3 BD4
VDO VDO VDO
BD3 BD4
F-2-56
2-38