Multiple Sheet Feed Prevention - Dell 5110cn Service Manual

Chapter 6 Principles of Operation

3.3.3 Multiple sheet feed prevention

The sheets set in a tray or a cassette may be stuck together at the edge due to microscopic curl-up
along the cutting plane caused by the guillotine, etc. The stuck sheets cause a multiple sheet feed or
a jam. The mechanism for separating these stuck sheets is called "ARRF (Active Separator Roller
Feeder) method". The Separator Roller is being pushed toward the MPF Roller by a spring tension.
The Separator Roller is coupled with the torque limiter (CLUTCH ASSY FRICTION), which prevents
the Separator Roller from being rotated by a torque below a certain level. When two sheets are fed
concurrently, the top sheet is separated from the bottom sheet by the friction between the Separator
Roller locked by the torque limiter thereby allowing only the top sheet to be fed. When only one
sheet is fed, two kinds of friction are concurrently generated between the MPF Roller and the sheet
(feeding force), and between the Separator Roller and the sheet (retaining force). However, the
friction by the Separator Roller is released because the Separator Roller rotates by the torque of the
MPF Roller. The release of the Separator Roller friction allows the sheet to be fed by the MPF
Roller.
Feed Roller (MPF)
Clutch Assy Friction (MPF)
Separator Roller (MPF)
Separator Roller (MPF)
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