Printronix P3000 Series manual Line Matrix Printing, Print Rate

Line Matrix Printing

Unlike moving–head dot matrix printers, Printronix P3000 Series printers create graphics and charac- ters by printing an entire dot row at one time. As shown in Figure 1–2, dots are printed in both direc- tions of shuttle travel at a printer stroke length of .4 inches to print through several character positions in 10 pitch Data Processing print mode. 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 advances 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 selected. Line spacing may be selected from the control panel or the host computer.

ONE

CHARACTER

ROW

DIRECTION OF SHUTTLE MOVEMENT

DOT

ROW START

1

2

3

4

5

6

7

8 *

9* *

10

11SPACE

12

1

2

1 HAMMER PRINT SPAN

*USED FOR LOWERCASE DESCENDER ONLY

**USED FOR UNDERLINE AND LOWERCASE DESCENDER

NOTE: P3000 shuttle sweeps through 4 character spaces at 10 cpi.

Figure 1–2. Line Matrix Printing

PAPER

ADVANCES

PAPER

FEED

PAPER

ADVANCES

Print Rate

The print rate, in lines per minute (lpm), is a function of the number of dot rows required to produce the character line regardless of the number of characters in the line. For example, more dot rows are re- quired to print lowercase characters with descenders; consequently, those characters are printed at a slower rate. Table 1–1 describes the print rate according to type of character printed and print mode. Complete printing specifications are provided in Appendix C.

1–4 Overview