Lexmark W820 - Optra B/W Laser Printer Service Manual page 53

Paper Stack Components
•
The Stack Tray Paper Sensor detects the presence of paper on the Stacker Tray.
•
The Stacker Tray Position Sensor detects the current position of the Stacker Tray
from the Liner Encoder. The Liner Encoder has three slits differently spaced along
the edge, and according to these differently spaced slits, the Stacker Tray positions
on the Finisher are classified into 25%, 50% and 100% positions.
•
The two sensors on the side of the Stacker Height Sensor detect the top surface of
the bundle of paper on the Stacker Tray.
•
Once the Stacker Tray moves down where the top surface of paper is below the
Sensor B, it moves up again. After the Sensor B detects that the top surface of paper
passed the Sensor B, the Stacker Tray moves up further by the specified level, and
then stops. This position is the Home Position (HP).
•
When the Sensor A detects the bundle of paper stacked on the Stacker Tray, the
Stacker Tray moves down where the top surface of paper is below the Sensor B, and
then moves up again to the home position.
•
When the bundle of paper on the Stacker Tray is removed and the Sensor B detects
no paper, the Stacker Tray moves up and down to the home position.
4025-Finisher
1-41
Introduction