Epson DFX-8500 service manual Printer Mechanism Operation, ‰Printhead, ‰Plunger mechanism

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.

Printhead

Paper Bail Assembly

Plunger

TIMING BELT, PF

Connector

Junction

Board

Tractor Assembly (Front)

RF Motor

PG Motor`

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.

Rev. B 2-1