Xerox Phaser 7750DXF, Service Manual

Page: 41 / 505

Theory of Operation 2-5
Paper Size Sensing
Trays 2 through 5 automatically sense the standard size media loaded in the printer by
using the paper size sensors mounted on the back inside of the printer. When paper is
loaded in the tray and the paper guides are adjusted, the levers on the bottom of the
trays change the size sensor actuator locations.
Actuating different combinations of the paper size sensors produces different
combinations of high and low signals, which tell the printer logic what size of paper
to display on the front panel, once the tray has been re-inserted into the printer.
Tray presence is also detected by the paper size sensor. Any actuation of the paper
size sensor signals the tray is present.
Paper Feeding and Sensing
Note
The tray feed / lift motor is a dual purpose motor, providing both the paper feed
and tray lift drive functions.
When the control logic calls for paper feed, the pick roller moves a sheet of paper to
the nip of the feed rollers and retard rollers. The rollers feed the paper to the takeaway
roller in the vertical transport where it is stopped and registered at the registration
roller.
Tray 5 Feed
Out Sensor
Tray 4 Feed
Out Sensor
Tray 2 Feed
Out Sensor
Takeaway
Sensor
Registration
Sensor
Registration Roll
Takeaway Roll 2
Feed Roller
Retard Roller
Pick Roll
Tray 2-5 Paper Path
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