Error message 13.20 means that when the printer was turned on or while the printer was trying to initialize one of
the sensors was detecting that there was media present. To clear this, remove the toner cartridge and check for an easily removable jam.
If none is found then pull the fuser out and check there, as this is the next easiest spot to check.
However, most often the machine has a jam in the front of the machine behind the MP/Tray 1 tray assembly. Remove the toner and cassette,
and use half a file folder to push through the cassette area to the top of the machine to remove any paper particles or free up a stuck
sensor flag that was caused from a previous jam. Don’t try this from the top to the bottom as you could break the sensor flag.
If you still have the error then removal of the MP/Tray 1 pick up assembly is needed (4200 & 4300 pickup assembly
4240, 4250, 4350 pickup assembly part # RM1-1097).
On these machines, unlike the original 4000 series, the sensor flag is actually on the feed roller assembly.
If you don’t find any paper debris then the sensor flag might be sticking. Before removing the sensor flag observe the spring
installation to make reinstallation easier. Remove the flag from the feed roller shaft and wipe down the shaft with alcohol then
reinstall the flag and check for proper movement.