Oce 3121, Technical & Service Manual

Page: 237 / 908

514 TSM Océ 3121 Laser Exposure System
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:
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.
Laser output Mode
High Text mode, text and photo mode
Medium Photo mode, Fax output
Low Printer output
DC controller PCB
24VU
FS
LMD
LOCK
Laser scanner motor drive PCB
Motor drive
circuit
Hall IC
output
6-facet mirror
Laser
scanner
motor
(M3)
DC control PBA
24VU
FS
LMD
LOCK
Motor drive
circuit
Hall IC
output
Laser scanner motor drive PBA
Laser
scanner
motor
(M3)
6-facet mirror