Operating Principles; Printer Mechanism Operation - Epson DFX-8500 Service Manual

OPERATING PRINCIPLES

2.1 PRINTER MECHANISM OPERATION

This section describes the Model 3I60 printer mechanism and explains how the printer works. The Model
3I60 printer mechanism features a 18-pin, impact dot printhead for serial printing. The printer mechanism is
the main component of the printer and is supported by the other components (the power supply and control
circuits). Figure 2-1 shows the Model 3I60 printer mechanism.
Figure 2-1. M-3I60 Printer Mechanism
The printer mechanism consists of the following main components:
‰Printhead :
The printhead is the component that actually prints characters (dot matrix patterns). Printing is performed by
striking the pins (arranged in a vertical line) against the surface of the paper and the ribbon. A character is
printed by repeating this printing operation in the horizontal direction (as the printhead moves). The printhead
includes a head fan and temperature sensor. The head fan also has a thermistor. When the printhead or fan
is too hot, the printer stops printing until it cools. (Refer to Section 2.3.9 Printhead Drive Circuit.)
‰Plunger mechanism :
During printing, the paper bail assembly holds the paper under tension so that it is fed smoothly. When paper
is loaded or ejected or when the tear off function is executed, the paper bail assembly needs to move up to
prevent a paper jam. The plunger moves the paper bail assembly up.
2-1
Rev. B