Service manual

REV.-A

Figure 2-1 shows the action of the printer mechanism when a single dot is printed.

Platen

Wire Resetting Spring

Stopper

\ \

Dot

Wire

Ribbon

Mask

.ctuatlngT:-Rbf)cl

B$l=lieaclDrivingCOil

Paper

Actuating Plate Spring

Figure 2-1. How the

Printhead

Works

The

printhead

tends to heat up after a period of continuous printing. To minimize the dot wire drive coil

overheating, the head is equipped with a thermistor that can detect the head temperature. When the

thermistor detects changes in the

printhead

temperature, the voltage signal changes. The CPU detects the

voltage change and stops printing until the head temperature cools.

.-.

---

“

The

printhead

is also used asa buzzer. Head driving coils move

allthedotwires

backandforth atafrequency

-.,,

{

of 1.5 KHZ for 40

I.M

without impacting the platen, so that the wires vibrate. The vibrating dot wires sound like

.=:

a buzzer.

-..

2-2