The Hammer Bank - Printronix P9012 Maintenance Manual

The Hammer Bank

In order to use matrix printing, you must have a method to print the required
dots. The P9012 uses the hammer bank.
The hammer bank contains a number of print hammers mounted on a shuttle
that can move back and forth horizontally. The shuttle prints a full line of
dots during each cycle of back and forth motion.
Each hammer consists of a stiff leaf spring attached at one end to the hammer
bank with a screw (Figure 2–4). The end opposite the screw has a pointed tip
attached. A permanent magnet keeps all the hammers retracted and under
tension. Each hammer has a magnetic coil which when energized counteracts
the permanent magnet, causing the hammer to release and strike the ribbon
and paper, leaving a dot (Figure 2–5). After printing, the rebounding hammer
is recaptured by the permanent magnet.
MAGNET
SHUTTLE SHAFT
Figure 2–4. Hammer and Shuttle Arrangement (Typical)
Principles of Operation
RIBBON
HAMMER BANK COVER
HAMMER TIP
COIL
COIL
RIBBON MASK
PAPER
PLATEN
HAMMER SPRING
PAPER IRONER
2–5