Paper Feed Mechanism / Operation - OKIDATA ML172 Series Service Manual

2.2.5 Paper Feed Mechanism / Operation

Paper Feed is performed by rotating the platen and pin tractors, which are driven by the linefeed stepper
motor.
The paper feed mechanism consists of :


Stepper motor with drive gear


Reduction gear


Platen - (no pins on ML172 Platen)


Optional Tractor unit (standard on ML172)


Pressure (friction feed) rollers - (no rear rollers on ML172)
PAPER FEED OPERATION
The paper feed stepper motor is mounted on the left side frame of the print unit, and it drives the platen via
the reduction gear. If the optional tractor unit is installed, platen rotation is also 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).
PAPER CLAMP MECHANISM (FRICTION FEED)
When the release lever is set to the OPEN position, the release link moves backward, and the front and
rear release links rotate counter-clockwise.
At the same time, the release shaft (interlocked with them) rotates counter-clockwise and places a gap
between the pressure rollers and platen, allowing paper to be inserted.
When the release lever is set to the CLOSED position, the release link moves forward, and the front and
Service Guide ML172/ML182 Series
Chapter 2 Principles of Operation
Page: 18