Print Pitches; Dot-Matrix Printing; The Print Head - Epson FX-80 User Manual

Chapter 3
Print Pitches
One of the big advantages the FX-80 printer has over a daisy-wheel
printer or a typewriter is the ability it gives you to easily vary the
width, or "pitch" of characters. To use this feature well, it's important
to understand just how the FX-80 prints. The technique used by the
FX-80 printer is called "dot-matrix printing."
Dot-Matrix Printing
To see how dot-matrix printing works, we need to look first at the
print head and then at the way characters are stored in the internal
memory of the printer.
The print head
A dot matrix is a grid or graph that a dot-matrix printer uses to plot
characters (which may be letters of the alphabet, numbers, or sym-
bols). On the FX-80 this matrix is nine rows of dots high and six col-
umns of dots wide. Look at any letter on your printout-it's made up
of a series of dots. And, as you can see in Figure 3-1, every letter fits
inside this six by nine grid. You may be wondering why the p dips
lower than the H. A few lower-case letters must descend below the
normal line of print (that's the seventh row from the top of the ma-
trix). All numbers, upper-case letters, and most symbols are formed
within the top seven rows of the matrix.
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