Impact printer

1

Impact printer
Wong Luen Mei Iris 4F (13) 2040073 3/1/2003
2
Printer is a kind of output device
Refers to a class of printer that work by banging
a head or needle against an ink ribbon to make a
mark on the paper. This includes dot-matrix
printer, daisy-wheel printer, and line printers.
In contrast, laser and ink-jet printers are
non-impact printers. The distinction is important
because impact printers tend to be considerably
noisier than non-impact printers but are useful
for multipart forms such as invoices.
3
A dot matrix printer
print quality Determined by the number of
pins (the mechanisms that print the dots), it can
vary from 9 to 24. The best dot-matrix printers
(24 pins) can produce near letter-quality type,
although you can still see a difference if you
look closely.
A dot matrix printer
4
Daisywheel Printer
Molded metal characters like those in a
typewriter are mounted on extensions attached to
a rotating wheel and are printed onto the paper
by means of a hammer and print ribbon.  
This results in a great deal of movement and
noise during the printing of documents, so
printing is slow (less than 90 cps). The
standard of print is similar to that produced by
an electric typewriter. As the characters on the
wheel are fixed, the size and font can only be
changed by using a different wheel. However, this
is very rarely done.
daisy wheels  
Daisy-wheel printers cannot print graphics, and
in general they are noisy and slow, printing from
10 to about 75 characters per second
5
Line Printer
A high-speed printer capable of printing an
entire line at one time. A fast line printer can
print as many as 3,000 lines per minute. The
disadvantages of line printers are that they
cannot print graphics, the print quality is low,
and they are very noisy
6
Special Features
7
Compare with non-impact printer and impact
printer

• quality of type The output produced by printers
  is said to be either letter quality (as good as a
  typewriter), near letter quality, or draft
  quality. Only daisy-wheel, ink-jet, and laser
  printers produce letter-quality type. Some
  dot-matrix printers claim letter-quality print,
  but if you look closely, you can see the
  difference.
• speed Measured in characters per second (cps)
  or pages per minute (ppm), the speed of printers
  varies widely. Daisy-wheel printers tend to be
  the slowest, printing about 30 cps. Line printers
  are fastest (up to 3,000 lines per minute).
  Dot-matrix printers can print up to 500 cps, and
  laser printers range from about 4 to 20 text
  pages per minute.

8

• impact or non-impact Impact printers include all
  printers that work by striking an ink ribbon.
  Daisy-wheel, dot-matrix, and line printers are
  impact printers. Non-impact printers include
  laser printers and ink-jet printers. The
  important difference between impact and
  non-impact printers is that impact printers are
  much noisier.
• graphics Some printers (daisy-wheel and line
  printers) can print only text. Other printers can
  print both text and graphics.
• fonts Some printers, notably dot-matrix
  printers, are limited to one or a few fonts. In
  contrast, laser and ink-jet printers are capable
  of printing an almost unlimited variety of fonts.
  Daisy-wheel printers can also print different
  fonts, but you need to change the daisy wheel,
  making it difficult to mix fonts in the same
  document.

9
Disadvantages and Advantages
10
Research from Internet http//www.yahoo.com http
//www.wedopedia.com http//www.whatis.com