Lifter-driver operation
The lifter driver keeps the media stack surface at a specific level in order to have a stabilized pickup
operation regardless of the size of the media in the tray 2 cassette. The dc controller PCA operates
the lifter-driver motor (M103) for 30 milliseconds. The motor stops when the paper-stack-position
sensor (PS107) detects the media. If the paper-stack-position sensor does not detect any media
within 8 seconds after the lifting operation has begun, the dc controller PCA determines that a lifter-
driver motor failure has occurred, and a message appears on the control-panel display (see
Resolving control-panel messages). The dc controller PCA stops the lifting operation if the paper-
stack-position sensor detects the absence of the tray 2 cassette.
Multifeed prevention
The MFP uses the separation roller in tray 2 to prevent multiple-feeding. The separation roller rotates
in the same direction as the feed roller. The separation roller is equipped with a torque limiter, but
because the force of the feed roller exceeds that of the torque limiter, the separation roller is actually
driven by the feed roller.
If multiple sheets of media are picked up, however, the low friction force between the sheets
weakens the rotational force from the feed roller to the separation roller. Consequently, the torque
limiter takes control of the separation roller and rotates it in the reverse direction, which removes the
extra sheets.
Figure 5-18 Multifeed prevention
110 5 Theory of operation
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