Printronix P7000 Series Maintenance Manual page 370

Chapter 7
Line Matrix Printing
When the shuttle reaches the end of a horizontal sweep, it reverses direction,
the paper advances upward one dot row, and the hammer springs print the
next row of dots as the shuttle moves in the opposite direction. When a line of
text characters is completed, hammer action stops and the paper advances to
the first dot row of the next print line. The number of dot rows used to
separate print lines depends on the vertical line spacing selected by the user.
The dot matrix patterns of text characters vary according to the font the user
selects. For example, in the data processing (DP) font at a line spacing of six
lines per inch (lpi), a dot matrix contains 12 dot rows from the top of one
character line to the top of the next. (Figure 58 and Figure 59.) At eight lpi
there are nine dot rows per character line, at nine lpi there are eight dot rows
per character line, and so on.
Each individual hammer spring can (and usually does) form more than one
character as the shuttle moves horizontally. This principle is illustrated in
Figure 60.
One
Text
Line
370
Direction of Shuttle Movement
Dot
Row
Start
1
2
3
4
5
6
7
8
*
9
* *
10
11 Number of rows determined by line spacing
n
1
2
* This row is used only for lowercase descenders
** This row is used for underlining and lowercase descenders
Figure 59. Standard Character Formation
Paper
Feed
Direction