Lexmark C91x Service Manual page 208

5055-xxx
Residual paper detection mechanism
The residual paper quantity in the tray is detected with four photo
interrupters. The quantity of pages remaining in the sheet feeder
displays in the following increments:
•
Near end, about 80 sheets
•
About 300 sheets
•
About 1,000 sheets
•
About 2,000 sheets
3-58
Service Manual