Lexmark 7462 series Service Manual page 676

Media level sensing
The media level for the media tray assembly is triggered by the actuator flag positioned in the two
photointerrupter sensors in the pick arm bracket assembly. The actuator flag blocks and unblocks the two
sensors in different sequence; it determines whether the paper tray is empty, low, or full.
250-sheet tray
Tray full
Tray low
Tray empty
550-sheet tray
Tray full
Tray low
Tray empty
Note: Media level sensing through sensor blocking sequence
Pick motor
The pick motor is activated to provide downward force at the pick roll through the pick arm gear train.
Sensor A & B
The photointerrupter sensors send signals to the engine; the media level status is empty, low, or full. An actuator
flag triggers the sensor by blocking it.
Sensor (pass-thru)
A photointerrupter sensor with a built-in flag that sends a signal to the engine where the media from the input
tray passes. This will trigger the pick arm to pick the next media.
Sensor (media empty)
Sensor A
unblocked
blocked
blocked
Sensor A
unblocked
blocked
blocked
Sensor (media low)
250-sheet drawer
assembly
Appendix C: Theory of operation
Pick arm assembly
676
Sensor B
unblocked
unblocked
blocked
Sensor B
unblocked
blocked
unblocked
Sensor
(pass through)
7462