Printronix P9000 Series manual Character Formation, Line Matrix Printing

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 assemF 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 adF 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 seF lected.

Overview 1-3