Service manual

5.2.5 Laser Synchronizing Detector Boards
Some of the optical components are made of plastic, and may expand and
contract with changes of temperature. If this happens, the number of pulses
in the laser main scan across the drum will vary. To counteract the effects of
this, the machine adjusts the gap between laser pixels to keep the number of
laser pulses in each main scan constant.
To do this, the machine has two laser synchronizing detector boards. They
are used to determine the number of clock pulses between the start and end
of each main scan. (These clock pulses are from the base clock, which is at
a much higher frequency than the laser pixel frequency.)
The laser synchronizing detector board-1 [A] synchronizes the main scan
start timing. At the other side, the laser synchronizing detector board-2 [B]
counts the number of clock pulses since detector board-1 was activated;
from this count and from the current laser pixel frequency, the machine can
calculate how many laser pixels there were across the main scan.
[A]
[B]
Detailed
Section
Descriptions
LASER EXPOSURE
SM 2-69 A166/A187/A189
CÓPIA NÃO CONTROLADA
CÓPIA NÃO CONTROLADA