Oce 3121 Technical & Service Manual page 237

Switching the Laser Output
The laser output can be: high, medium, or low. Thus ensuring the best image
for the selected mode. The output is limited by the output signal "intensity se-
lection signal 0, 1, 2" from the image processor PBA.
The laser output is used for its respective mode, as shown:
Laser output
High
Medium
Low
Controlling the Scanner Motor
The scanner motor rotates in accordance with the instructions received from
the DC control PBA. The power supply is controlled by the scanner driver
PBA.
The scanner motor (M3) rotates when the laser scanner motor drive signal
(LMD=1) is sent, by the DC control PBA, to the scanner driver PBA. At this
time, the hall IC signal is returned from M3. This signal is used to control the
power supply for M3.
The timing of the power supply is controlled in phase with the rotation refer-
ence pulses (FS) from the DC control PBA. Thus ensuring a specific speed of
rotation.
DC control PBA
DC controller PCB
514 TSM Océ 3121
Laser scanner motor drive PBA
Laser scanner motor drive PCB
24VU
24VU
FS
FS
Motor drive
circuit
LMD
LMD
LOCK
LOCK
Mode
Text mode, text and photo mode
Photo mode, Fax output
Printer output
Motor drive
circuit
Hall IC
Hall IC
output
output
6-facet mirror
6-facet mirror
Laser
Laser
scanner
scanner
motor
motor
(M3)
(M3)
Laser Exposure System