Lexmark C520 Series Service Manual page 44

5022-xxx
Paper pick sensor
Paper exit/duplex entry sensor and bin full flag
The top sensor detects movement in two directions: as the paper exits the fuser and as it is retracted from the
exit tray back into the duplex path. Each sheet must be driven past the fuser exit flag and allowed to fall before
being turned around and starting the duplex path. If the print media activates the paper exit flag for too long, or
the print media doesn't reach the paper exit flag within a given time, a paper jam error will be posted.
There is a similar paper flag (bin full) on the output of network machines. This sensor indicates when the output
bin is full. The physical flag is located in the fuser on all machines; however, the electrical sensor is not present
on the non-network models. The flag should move in and out of the sensor eye with every sheet until the bin is
nearly full. Once in this state, the paper flag will break the sensor eye continuously.
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Service Manual