Gestetner G060 Service Manual page 249

LASER EXPOSURE
6.3.3 LASER SYNCHRONIZING DETECTOR
[B]
[B]
[A]
[A]
G060D202.WMF
Overview
The machine has four laser synchronizing detector boards (LSD), one at each
corner of the laser optics housing unit.
Each pair of boards detects two colors. The machine recognizes each color from
the time that they are detected. The two LSDs [A] at the right are used for magenta
and cyan, and the two [B] at the left are used for yellow and black.
Main Scan Start Detection
For magenta and cyan, the LSD at the rear detects the start of the main scan. For
yellow and black, the LSD at the front detects the start of the main scan.
Clock Frequency Adjustment
Each pair ensures that the number of laser clock pulses in the main scan is
constant. If the count for one particular beam varies from normal, the LD clock
frequency for that beam is adjusted.
If the board at the end position is defective, this cannot be detected. Switch the
detection feature off with SP2-919-1.
SM 6-19 G060