Canon imageRUNNER ADVANCE C5051 Series Service Manual page 69

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Technology■>■Laser■Exposure■System■>■Various■Controls■>■Horizontal■scanning■synchronous■control
■ Laser■ON■/■OFF■control ■
● Purpose
■
Laser■light■is■turned■ON■/■OFF■according■to■the■combination■of■laser■control■signals.
● Execution timing ■
After■the■power■ON
● Control detail ■
DC■Controller■switches■the■4■modes■(forcible■OFF■mode,■APC■mode,■Print■mode■and■standby■
mode)■according■to■the■laser■control■signal.
Laser control signal
DC Controller (UN1)
Video signal
Mode Laser■status
Forcible■OFF■mode OFF Light■intensity■setting■decided■on■APC■is■cleared.
APC■mode ON Laser■light■intensity■adjustment
Print■mode ON■/■OFF Laser■is■emitted■according■to■the■video■signal.
Standby■mode OFF Host■machine■is■in■standby■status.
Print Image formation
ready timing
instruction
PSTBY PINTR
At 1st line (APC)
LaserA
LaserB
LaserC
LaserD
Mode Standby
APC mode APC mode / Print mode
name mode
2 Technology■>■Laser■Exposure■System■>■Various■Controls■>■Horizontal■scanning■synchronous■control
Laser Driver
Scanner mirror
PCB
Laser beam
Remark
PRINT LSTR PSTBY
At 2nd line (APC)
At 3rd line (APC)
At 4th line (APC)
Forcible Standby
OFF mode
■
■ Horizontal■scanning■synchronous■control ■
● Purpose
■
This■is■to■align■the■writing■start■position■in■horizontal■scanning■direction.
● Execution timing ■
Per■1■line
● Execution time ■
Approx.■7.5µs
● Control detail ■
1)■DC■Controller■forcibly■emits■the■laser■diode■on■M-laser■driver■PCB■by■setting■the■laser■
control■signal■of■M■-laser■to■APC■mode.■Also,■DC■controller■forcibly■emits■the■laser■diode■of■
Bk■laser■driver■PCB■by■setting■the■Bk■laser■control■signal■to■APC■mode.
2)■Concerning■the■laser■beam■of■M■laser,■there■is■a■BD■sensor■(Y,■M)■on■the■scanning■light■
path■and■the■laser■bean■is■emitted■to■the■BD■sensor■(Y,■M).■Regarding■the■laser■beam■of■Bk■
laser,■there■is■a■BD■sensor■(C,■Bk)■on■the■scanning■light■path■and■the■laser■beam■is■emitted■
to■the■BD■sensor■(C,■Bk)■as■well.
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3)■Two■BD■sensors■detect■the■laser■beam,■create■the■BD■signal■(BD_YM,■BD_CBk)■and■send■
it■to■the■DC■controller.
4)■DC■Controller■executes■synchronous■control■based■on■this■signal■and■sends■the■standard■
BD■signal■to■Main■Controller■as■a■horizontal■scanning■synchronous■signal■(BD)■per■1■line.
5)■When■Main■Controller■receives■those■signals,■it■outputs■the■video■signal■(VDO_Y,■VDO_
M,■VOD_C,■VDO_Bk)■to■DC■Controller.■As■a■result■of■this,■the■Laser■Driver■emits■the■laser■
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beam■from■the■specified■position■for■each■line.
mode
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