Specifications

2–4
Principles of Operation
The Hammer Bank
The LG12 uses a hammer bank to print dots. The hammer bank consists of
88 hammer springs mounted on a shuttle that moves horizontally back and
forth. The hammer bank prints one horizontal line of dots during each
horizontal sweep of the shuttle.
A hammer spring is a stiff leaf spring with a hardened steel tip at the upper
end, and is attached to the hammer bank at the lower end. (See Figure 2–3.)
A permanent magnet keeps the hammer springs retracted and under tension.
Behind every hammer is a pair of magnetic coils which, when energized,
neutralize the field of the permanent magnet. This releases the hammer,
which springs forward and strikes the ribbon and paper, leaving a dot. The
hammer is recaptured by the permanent magnet as it rebounds. (See
Figure 2–4.)