Page: 32
Service Guide ML390/391
Chapter 2 Principles of Operation
2.4.04 Paper Feed Mechanism
The paper feed mechanism consists of the following items.
· Line Feed Motor (with drive gear)
· Reduction Gear
· Platen
· Push Tractor Unit
· Pressure Rollers (friction feed rollers)
· Pull Tractor Unit (optional)
Paper Feed Operation
The line feed motor is mounted on the left side frame of the printer. It drives the platen via the reduction
gear. If the optional tractor unit is installed, platen rotation is transmitted through the idle gear to the tractor
unit.
The paper feed mechanism is designed so when the stepper motor rotates 48 steps (360 degrees), paper
is fed 0.17 inch (4.23 mm).
Friction Feed