Xerox Phaser 8400 Service Manual page 46

Transfix System
The transfix roller applies pressure to the back side of the paper as it moves between
the transfix roller and drum. This pressure transfers the image from the drum to the
paper. A set of springs determines how much pressure the transfix roller applies in the
load module against the drum. The pressure must be uniform across the length of the
transfix roller to avoid paper wrinkles and light spots on the prints.
After the transfix roller engages, the drum rotates to advance the paper during the
transfix process. The drum continues to advance the paper until the transfix roller
disengages. The action of the process drive lifts and lowers the transfix roller. The
upper gears of the process drive move to rotate the transfix camshaft to bring the
transfix roller into contact with the drum. The gears reverse to rotate the transfix roller
back to its original position, except when printing from Tray 1 or on envelopes. The
transfix load springs and double lever arms increase the force when the camshaft
engages.
Warning
Never attempt to adjust or increase the transfix pressure on the springs.
s8500-021
2-18 Phaser 8400/8500/8550 Color Printer