Oce 3121 Technical & Service Manual page 566

Alignment of the fusing film
Outline
1
During rotation, the fusing film tends to run towards the front or the rear of the
machine. This movement is monitored by the film sensor PS2. The motor M5
is used to correct the alignment.
The lower roller is released when the front door is open.
Warning:
Switching the machine ON could, in such cases cause misplacement of the film
or damage to the heater.
Ensure that the roller is locked when working with the front door open.
The alignment sensor PS2 rests against the edge of the fusing film. The rear
edge of the fusing film is not straight, causing the alignment sensor to contin-
ually switch ON and OFF.
If the film is correctly aligned, the time of the ON and the OFF periods is the
same. If the film traverses to the rear, the sensor will remain ON longer than it
remains OFF. If the film traverses to the front, the sensor will remain OFF
longer than it remains ON. The DC control PBA compares the ON and OFF
times, so correcting the position of the film.
ed.1 17 Fusing 509