Gestetner B147, Service Manual

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PHOTOCONDUCTOR UNIT
SM 6-51 B147/B149/B190
Detailed
Des
cription
s
6.7.3 DRUM GEAR POSITION SENSORS
Mechanism
The machine uses these sensors to detect if the drum motors rotate. When it
detects that the drum motor is not moving, SC440 appears. These sensors also
help the machine to initialize the relative positions of the gears when turning on the
main switch and initializing. This prevents phase fluctuation between printouts.
There is an interrupter [E] on each of the black [D] and yellow [C] drum gears. The
drum gear position sensors [F][G] detect the positions of these interrupters
respectively. The sensors check that the two interrupters are parallel. This
mechanism makes sure that output quality does not vary. The cyan [B] and
magenta [A] drum gears operate with the yellow drum gear because these three
drum gears are linked through other gears [H][I].
In the ready status, the two interrupters stay in a parallel position. If they are not in
a parallel position (as shown in the illustration), the machine adjusts the position of
the black drum gear.
B146D530.WMF
[B]
[A]
[C]
[D]
[G]
[F]
[I]
[H]
[E]