LQ-300 Service Manual Oparating Principles
2.1.3 Paper Handling Mechanism
During
normal
operation, paper is fed to the printer, advanced to the specified position, and
ejected from the printer. These functions are performed by various paper handling mechanisms,
such as the
&actors,
rollers, and gears. This section describes the paper handling mechanism for
this printer.
2.1.3.1 Paper Feed Mechanisms
Cut sheets are fed by friction. Continuous paper is fed by a tractor. There are three ways to feed
with tractors: the push tractor method, the pull tractor method, and the push-pull tractor method.
During normal operation, the printer is set up with only one tractor, which functions as either a
push or a pull tractor, depending on where it is attached on the printer. To use the push-pull .
.
tractor feed method, an optional tractor must be attached.
There are two ways to insert paper into the printer. Cut sheets use the top entrance and continuous
paper uses rear insertion.
2.1.3.2 Paper Advance Mechanism
This section describes how the friction and tractor advance mechanisms feed paper through the
printer. The paper advance mechanism consists of the
PF
motor, platen, driven roller assembly,
driven roller cover, tractor assembly, knob,
PF
gear train, etc. The
PF
motor can drive the platen
both forward and in
reveme.
Friction Advance Method
Paper is held by the platen, the
PF
driven roller, and the eject roller assembly. Turning in the
direction of the black arrows, the
PF
motor pinion gear drives the paper advance reduction gear.
The paper advance reduction gear turns the platen gear,
PF
driven roller, and the platen. The
platen drives the driven roller cover; then the driven roller cover drives to eject the paper. The
paper advances in the direction of white arrows.
Figure 2-3 shows the friction advance method
when the paper is fed through the top paper entrance.
Driven Roller Cover
Driven PF Roller
Figure 2-3. Friction Advance Mechanism
Rev.A
2-3
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