Printing Mechanism - Epson LQ-1050 Technical Manual

2.1.2.1 Printing Mechanism

The printing mechanism includes the printhead, inked ribbon, and platen. Figure 2-3 shows the printing
mechanism and Table 2-2 lists the printhead specifications. The printhead has 24 dot wires which are
arrayed in two 12 wire lines. Each dot wire is connected to its own drive coil.
The basic printing operations are as follows:
The drive signals, transferred from the control circuit to the printhead drive circuit, are converted
into printhead drive voltages which energize the head driving coils for the dot wires. The coil is
therefore magnetized which generates a magnetic force in the iron core.
2. Because of this force, the iron core attracts the actuating plate which is in contact with the dot wire,
and the dot wire is pushed toward the platen.
3. The dot wire strikes the inked ribbon and the paper against the platen to print a dot on the paper.
4. When the coil is de-energized, the iron core loses its 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.
Stopper
Actuating Plata "
This is the sequence used to print a dot on the paper. The printhead contains a thermistor to monitor
its temperature so that the dot wire drive coils are protected against overheating. The printhead
temperature detected by the thermistor is converted into a voltage and fed back to the control circuit,
to provide a mechanism for printhead protection. Refer to Section 2.3.5.2 for details.
Pin Diameter
Type
[mm]
Impact dot
Dot Wme
Fig. 2-3. Printing Mechanism
Table 2-2. Printhead
Dot Pitch
["1
0.2 1/1 80
Paper
Specification
Pin Drive Voltage
Configuration [v]
12 line X 2
2-4
Drive pulse
width [I&]
35 379
Sensor
Thermistor