Laser Emission Timing (Sos Signal - Minolta Di 620 Manual

1155SBM1002A

10-2. Laser Emission Timing (SOS Signal)

The SOS-EXE ENBL signal from the Master Board forces the firing of the laser. The
laser beam moves to the polygon motor, then through the lenses, then reflects off
the SOS Mirror and hits the SOS Sensor Board, which generates the SOS signal.
Polygon Motor (M4)
f-θ Lenses
SOS Mirror
SOS signal output operates with respect to only one of the two laser beams. The
SOS Sensor Board has two photoreceptors (A and B) set along the laser path. The
A and B waveforms are therefore offset with respect to time, as the laser moves first
across A and then across B. The point at which the two waveforms cross (Point C,
below) gives the SOS signal output time.
This SOS signal determines the laser emission timing for two lines in the main
scanning direction.
LD Light
SOS Sensor Board
A B
1155M088CA
1155M088CA
M-51
Output
Output from A
C
SOS Sensor Board
(PWB-G)
1155M009AA
Output from B
Time
1155M089CA
1155M089CA