Specifications

2.3.2 The Paper Drive Assembly
Two sets of synchronized six-pin tractors (upper and lower) control paper
motion.
The motor driving the tractors is driven by drivers and logic on the
SMMC board.
2.3.3 The Ribbon Assembly
The ribbon is housed in a plastic cartridge and is pulled between the
print actuator modules and the paper by a data-responsive motor. The
ribbon is about 60 meters (65 yards) long, 25 mm (1 inch) wide, and can
be re-inked once only (see the LG31 Installation/Operator’s Manual).
The ribbon is joined by welding the two ends together to form a Mobius
strip. To prevent the weld causing problems to the print actuator
mechanism, a ribbon weld sensor is fitted. This detects a hole in the
ribbon weld and suspends printing for a few seconds to allow the weld
to clear the printing area. This ribbon weld sensor also inhibits printing
when the ribbon breaks.
2.3.4 Print Actuator Assembly
This assembly puts the dots on the paper. It is a set of three removable
actuator modules, mounted on a horizontally moving bed.
This assembly, a balance weight, the mounting springs and the mass of
the moving part of the motor, have been tuned to a resonant frequency
of approximately 20 Hz. The SMMC board drives the motor at this
frequency.
2.4 Electronics
2.4.1 Overview
There are seven main elements to this subassembly. Of these, four
boards plug into a mother board on which there are no active elements.
Figure 2–4 is a simplified block diagram of the printer electronics. The
seven main elements are:
1. Shuttle Control Panel Interface (SCPI)
2. Shuttle Matrix Display Panel (SMDP)
3. Shuttle Matrix System Microprocessor (SMSM)
THEORY OF OPERATION 2–7