Setting; Adjusting The Photosensors - Olivetti PR2 Service Manual

4.6 SETTING

4.6.1 ADJUSTING THE PHOTOSENSORS

The printer's photosensors are adjusted at the factory. However, a change of the electrical
characteristics of the photosensors used or the use of non-standard paper may require that the
photosensors be readjusted at the customer's site.
All the photosensors in the printer need adjusting. The following are installed:
- Paper presence photosensors.
These consist of two LEDs and two photoreceivers that are the first to detect the loading of a
document through the front insertion slot. The ray of light is transmitted by fibre optics.
- Paper front alignment photosensors.
These are included in the same group as the paper presence photosensors and are indicated in
this manual as front photosensor group.
The paper front alignment photosensors check the alignment of the paper before it reaches the
print head. They consist of four LEDs and four photoreceivers, all connected through fibre optics.
- Autoborder photosensor.
Fitted behind the print head, this photosensors measures the width and length of the paper so that
the position of the first print column can be measured. This photosensor also makes it possible to
check the print interruption or carriage return functions in case the paper is narrower than the print
line length value sent by the system. This photosensor also resets the print carriage.
- Paper rear alignment photosensor.
Consists of a LED and photoreceiver connected through a fibre optic. This photosensor checks that
the paper is correctly aligned at the rear output slot so as to avoid possible paper jams.
The figure on the next page shows the location of the individual photosensors on the printer.
683311W
Service Manual
4-27