Printronix P9000 Series - Manual (Page 15)

1-3 Overview
Character Formation
The P9012 printer generates characters by assembling groups of dots in matrices. Dots overlap
to produce a solid appearing character (Figure 1-1). Dot impressions are made by an assemĆ
bly of 88 hammers installed on an oscillating shuttle. The hammers impact the paper through a
moving ink ribbon. Horizontal shuttle movement and vertical paper advancement combine for
precise dot printing to form the character.
Figure 1-1. Typical Character Formation
Line Matrix Printing
Unlike moving-head serial dot matrix printers, the Printronix P9012 printer creates graphics
and characters by printing an entire dot row at one time. Dots are printed in both directions of
shuttle travel at a printer stroke length of .15" to print through 1.5 character positions in 10
pitch Data Processing print mode (Figure 1-2). By printing a row of dots, line matrix printers
achieve higher print duty cycles than moving head dot matrix (serial) printers.
During each sweep of the shuttle, hammers are activated to print dots at selected positions in
that dot row. When the shuttle reaches the end of a sweep, it reverses direction, paper advances
one dot row, and the hammers print the next consecutive row of dots.
After an entire line of characters is printed, hammer print action ceases and the paper adĆ
vances to the first dot row of the next print line. This creates a series of blank rows between lines
of characters. The number of rows allowed for line separation depends on the line spacing seĆ
lected.