Specifications

The operator can cause printing to continue by pressing TEST
CLR momentarily. [L P P] then replaces [L o P] in the dis-
play, and the printing process continues until ‘‘end of paper’’ is
reached. At this point [L P P] is replaced by[Po]andprinting
ceases.
4. Shuttle Access Door Interlock Switch
The function of the shuttle access interlock switch is to discharge
the 85V and 42V bus voltages via the SPSD board as described in
Section Section 2.5.5 and to remove the mains ac power input in the
power supply circuit.
5. Top Cover Interlock Switch
This switch is located at the top left of the printer. It is a three-
position safety interlock switch. When the top cover is raised, the
printer will only operate when the switch is manually lifted.
2.2.2 Fans
The two fans are driven by the SMMC board. They are controlled in
accordance with the printing duty cycle of the printer.
2.3 Print Mechanism
2.3.1 Description
The LG31 Printer uses dot matrix technology. There are 33 print
actuators, arranged in three identical Print Actuator Modules with 11
actuators each. They span a printing width of 13.2 inches. Characters
are built up by a print pin impacting the paper through an inked ribbon.
Each print pin is the moving core of a solenoid. The coil of the solenoid
is known as the Print Actuator. Each print pin is driven by a pulse of
current through the print actuator.
Each print pin prints in a horizontal space, 0.4 inches wide. This
space can be organized into characters or graphics. When printing draft
characters for example, each pin prints four characters.
The horizontal movement of the print actuators is powered by a resonant
shuttle motor. This motor moves the complete assembly of 33 actuators
across the width of the paper in 25 ms. Thus, one complete line of dots
can be printed in 25 ms.
THEORY OF OPERATION 2–5