Auto Power Control (Apc) - Ricoh R-C4 Service Manual

LASER EXPOSURE 21 July 2006

6.6.2 AUTO POWER CONTROL (APC)

IPU LD Drive Board
+5V
PD LD
LD Driver
LD LEVEL
LD ON
LD OFF
LD
Controller
VIDEO
VREF
Reference
Circuit
B205D510.WMFF
The LD driver IC drives the laser diode. To prevent the intensity of the laser beam
from changing because of the temperature, the machine monitors the current
passing through the laser diode (LD). The machine adjusts the current to the laser
diode by comparing it with the reference level from the reference circuit.
This auto power control is done just after the machine is turned on and during
printing while the laser diode is active.
The laser diode power is adjusted on the production line.
NOTE: Do not touch the variable resistors on the LD unit in the field.
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