Xerox Phaser 6128MFP Service Manual page 74

Theory of Operation
Lead Edge Registration
Paper Size Control
2-20
When a sheet is fed from the Tray to the toner transfer position, the registration of
the sheet may not be correctly maintained due to misalignment of lead edges in
the tray.
To avoid this problem, the lead edge position needs to be aligned at the
Registration rollers before the sheet is fed in front of the Transfer Belt, or in front of
the BTRs.
Before the registration rollers are energized, the paper is advanced from the tray to
the rollers. This process aligns the leading edge as shown below.
By pushing the edge of the sheet against the registration roller that is not turning,
the lead edge of the sheet is registered.
Registration Rollers
Skewed Paper
The printer doesn't have switches for detecting paper size, and the length of paper
is detected only by the Registration Sensor when feeding paper. If printing data
and paper size don't match, an error is sent to the Image Processor board.
Registration Rollers
s6128-021
s6128-022
Phaser 6128MFP Service Manual