Computer Interfacing

Printers

Figure

9.2 The

printing mechanism

of a

cylinder head printer

slow and noisy. The paper normally came in unperfo-

rated, continuous rolls of about 8.5 in width, rather less

convenient perhaps, than the perforated fan-fold paper

in common use today.

Dot-matrix printers

A matrix in this sense is a two-dimensional array of dots,

capable of representing any of a very wide range of char-

acters,

alpha-numeric or graphical. The image is

produced by striking the paper through an inked ribbon,

much like that of a typewriter. But here the resemblance

ends.

Whilst the typewriter forms each character with a

single stroke, the dot-matrix printer