Epson LQ-2550 Technical Manual page 52

2.1.2.1 Printing Mechanism
The printing mechanism consists of two parts: The printing mechanism composed of the printhead,
ink ribbon and platen, and the printhead cooling mechanism composed of the printhead fan.
Printing Mechanism
Figure 2-3 shows the printing mechanism.
The printhead has 24 wires arranged in two staggered
connected to their own wire drive coils. The printhead
The basic printing operations are as follows:
The drive signal is sent from the control circuit to the printhead drive circuit and converted to the
coil in the printhead. This magnetizes the coil and the iron core.
This magnetism pulls the actuating plate to the iron core, and the dot wire attached to the plate is
2.
pushed toward the platen.
3. The dot wire strikes the inked ribbon and paper against the platen to print a dot on the paper.
4. When the coil is de-energized, the iron core loses it magnetic force so that the actuating plate returns
to its initial position under the action of the actuating plate spring. After having struck the platen,
the dot wire also returns to its initial position under the action of impact energy and the wire resetting
spring, and is held in contact with the actuating plate until it is driven again.
This is the sequence used to print a dot on the paper.
Wtre Reaatwtg Spring
Stopper
Dot Wwe
Figure 2-3. Printing Mechanism
2-5
lines (12 wires for each line). These wires are
specifications are listed in Table 2-2.
Papar
REV.-A
Platen