Chapter 17: Printers^403
Eventually, as the personal computer became popular, a need for PC printers was rec-
ognized by a number of manufacturers who had been making printers for mainframe
and minicomputer systems. As opposed to the large, high-speed line printers used on the
larger systems, PC printers needed to be low in cost and simple to operate.
Daisy Wheel Printers
The earliest printers were daisy wheel printers, an easy adaptation from typewriters that
used the same mechanism. The print mechanism is a plastic or metal wheel that rotates to
position the letter to be printed into position in front of a print hammer that strikes the let-
ter into an inked ribbon and onto the paper. The raised letters and special characters are
located on to a flexible arm emanating from the center ring of the wheel. The arms of the
daisy wheel are like the petals of a daisy, which is where it gets its name.
Daisy wheel printers, which are largely obsolete today, are the standard for what is
called letter-quality (letter meaning character and not document) printing. Since the print
mechanism is virtually a typewriter that prints one character at a time, the daisy wheel
was an excellent printer for high-quality documents and multipart forms. These printers
could only produce the characters on the daisy wheel and could not produce graphics at
all. In spite of their print quality, daisy wheel printers are very slow and quite noisy.
These two problems, along with the limitation of printing text characters only, quickly
lead to the virtual disappearance of daisy wheel printers.
Figure 17-1. A teletype incorporated a keyboard and a printer into a single terminal