Specifications

and optional scanning heads (which replace the normal print head). Although portable printers can’t
compete in features or speed with desktop printers, they enable travelers to deliver a high-quality
printout anywhere.
All-In-One/Multifunction Devices
If you are short of space and money, an all-in-one or multifunction device that combines print, scan,
copy, and sometimes fax features might seem like a desirable alternative to purchasing two or more
separate devices. You’ll certainly save some money by doing so; you can buy a typical inkjet-based
printer/copier/scanner for as little as $150 (which is little more than a good inkjet printer costs by
itself).
What might you lose when you put all your digital eggs in one basket by using a multifunction
device?
■ Lower print speed. The print mechanisms found in low-cost all-in-one units can run at speeds sig-
nificantly lower than those found in most inkjet printers from the same vendor. Laser-based all-
in-one units often come closer to keeping up with the printer-only siblings.
■ Less sophisticated print features. The print mechanism in an inkjet-based all-in-one unit also
might lack the latest high-resolution and color-layering print features found in the standalone
inkjet printers. Laser-based all-in-one units often match their printer-only siblings resolutions
and output options, though.
■ Lower scan resolutions. Whether you choose a sheet-fed model or the increasingly popular flatbed
all-in-one models, you are often limited to 600dpi scans. These are acceptable for scanning full-
size documents but are a limiting factor if you want to enlarge small photos, documents, or
details from photos.
Because models change frequently, you should compare the printing and scanning features of any
multifunction device you are considering to printers and scanners from the same vendor. Keep in
mind that if you also need a copier and fax machine, most (but not all) multifunction devices also
feature these options, and you might find that a multifunction device will be used primarily for those
tasks with just occasional use as a printer or scanner.
Dot-Matrix Printers
Dot-matrix printers were, at one time, the most popular type of printer on the market because they
were small, inexpensive to buy and to run, and fairly reliable. As the price of laser printers steadily
dropped, however, and inkjet printers came to market that offered far superior output quality at virtu-
ally the same price, the market for dot-matrix printers contracted dramatically. Although they con-
tinue to perform certain tasks quite well, dot-matrix printers generally are too noisy, offer mediocre
print quality, and have poor paper handling for single-sheet paper.
Unlike lasers and most inkjets, dot-matrix printers do not process documents a page at a time.
Instead, they work primarily with a stream of ASCII characters up to a line at a time and therefore
require very small memory buffers. As a result, their speed is measured in characters per second (cps)
instead of pages per minute. In addition, very little processing is performed in the printer when com-
pared to a laser printer. Dot-matrix printers do not use complex page description languages such as
PCL and PostScript. The data stream from the computer contains escape sequences used to set basic
printer parameters, such as page size and print quality, but any complex processing required is per-
formed by the PC.
Dot-matrix printers work by advancing paper vertically around a rubberized roller, called a platen, one
line at a time. At the same time, a print head travels back and forth horizontally on a metal bar. The