Carriage Unit; Paper Handling Mechanisms - Epson FX-880 Service Manual

Operating Principles

Carriage Unit

The carriage unit transports the printhead back and forth across the printed page. It is driven by the
carriage (CR) motor—a stepper motor—via the timing belt, which connects to the underside of the
carriage. The carriage slides along the carriage guide shaft, which maintains the printhead's horizontal
alignment with the platen, while the base frame provides further support and maintains the printhead's
vertical alignment. The home position (HP) sensor detects the home position of the carriage at power-on
and when the CR motor changes direction.
Carriage Guide Shaft
Figure 3. Carriage Unit

Paper Handling Mechanisms

Cut sheets are fed by friction. Continuous paper is fed by tractor. There are three ways to feed paper 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 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.
The paper release lever is used to switch PF motor torque between cut sheet (friction) feeding and
continuous paper (tractor) feeding. In addition, the paper release sensor detects the release lever's
setting position. This lets the main logic board know what type of paper is loaded and how many lines to
print per page. (Cut sheets print at 61 lines per page, while continuous paper prints at 66 lines per page.)
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EPSON FX-880/FX-1180 Service Manual