HP LineJet Série Guide De Référence Rapide page 35

Tractor Door
12.
Load the paper onto the right tractor sprockets and close the
tractor door.
13.
If necessary, unlock and slide the right tractor to remove paper
slack or to adjust for various paper widths. Then, lock the
tractor.
Horizontal
Adjustment Knob
14.
After both tractors are secured, you may use the horizontal
adjustment knob to make fine horizontal paper adjustments.
35
Loading Paper
Tractor Lock