Xerox Phaser 6180MFP Service Manual page 136

Theory of Operation
2-54
However, when two sheets are fed concurrently, only the Feed Roller rotates.
The Retard Roller is coupled to a friction clutch that prevents the roller from
rotating due to extra force from feeding two sheets; this process allows the
upper sheet to pass by as the lower sheet is stopped by the friction with the
Retard Roller at rest.
The Retard Roller is pushed toward Feed Roller by spring pressure, and
controlled by the Friction Clutch with which it is coupled.
Feed Roller (Takeaway Roller)
Retard Roller (Separator)
Friction Clutch
Retard Roller (Separator)
Feed Roller (Nudger Roller)
Phaser 6180MFP Multifunction Printer Service Manual
Multiple Feed
s6180mfp-042