Service manual

Operating Principles
EPSON FX-880/FX-1180 Service Manual
2-3
As shown in the diagram below, the head driving coil, when energized, pulls against the actuating plate.
This thrusts the dot wire against the ink ribbon and creates a printed dot. (The ribbon mask prevents the
ribbon from smudging the paper as the printhead moves back and forth across the page.)
After striking the ink ribbon, the driving coil is shut off and the dot wire returns to its original position. This
is accomplished by the wire resetting spring, which is aided by the rebound action of the dot wire hitting
the platen.
Since the printhead heats up after a period of use, it is equipped with a thermistor to detect head
temperature. Voltage changes reflecting changes in the thermistor’s resistance are output to the CPU.
Should the printhead overheat, the CPU detects this and automatically stops printing until the printhead
cools.
Pivot
Figure 2. Printhead Drive Coil Mechanism