Theory of Operation 2-35
Gear Layout
Functional Components
Two-sided printing is enabled by mounting the Duplex Unit on the rear side of the
base engine.
Duplex Unit Switch This switch detects that the Duplex Unit Lower Housing and
Duplex Unit Housing Cover are closed.
Duplex Unit Sensor This sensor detects the presence or absence of paper in the
Duplex Unit.
Duplex Unit Fan This fan vents air within the Duplex Unit and takes in outside air,
to prevent abnormal temperature rise in the Duplex Unit.
Duplex Roller This roller feeds the paper having the printed first surface back into
the printer through the Duplex Unit, to print on the second surface.
Duplex Unit PWBA The CPU on the Duplex Unit PWBA receives instructions
from the HVPS/Engine Logic Board and information from sensors and switches, and
controls paper transport through the Duplex Unit.
1. Roller Gears 4. Idle Gear 49
2. Idle Gear 29 5. Duplex Unit Motor
3. Idle Gear 39 6. Idle Gear 67/29
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