Specifications

■ Dot matrix. Dot-matrix printers use an array of round-headed pins to press an inked ribbon
against a page. The pins are arranged in a rectangular grid (called a matrix); different combina-
tions of pins form the various characters and images. A few non-impact printers also use a dot-
matrix print head with heat-sensitive ribbons, but these printers are primarily for portable use.
Although dot-matrix printers are largely absent from today’s offices, they are still merrily
whizzing away in warehouses, stores, and other locations where their capability to print multi-
part forms is valued.
Note
A fourth option, daisywheel, which created fully formed characters similar to typewriting, was popular in law offices
during the early days of PCs but has been replaced by laser printers.
In general, laser printers provide the best quality output, followed closely by inkjet, with dot-matrix
printers coming in a distant third. Dot-matrix printers have become largely relegated to commercial
applications requiring continuous feed and multipart forms. Inkjet printers have become important
parts of SOHO (small office, home office) printing because of their high print quality (rivaling less
expensive lasers for text), color capabilities, versatility, and inclusion in many popular “all-in-one”
printer-scanner-fax units. In addition, high-end units increasingly are found in corporate offices and
graphic arts departments. Laser printers continue to be the best choice for text-based applications
because of their speed, print quality, and low cost per page.
Most printers use the same basic terminology to describe their features and capabilities. The following
sections examine some of this technology, how (or if) it applies to the various printer types, and what
you should look for when shopping for a printer.
Print Resolution
The term resolution is used to describe the sharpness and clarity of the printed output. All these
printer technologies create images by laying down a series of dots on the page. The size and number
of these dots determine the printer’s resolution and the quality of the output. If you look at a page of
text produced by a low-resolution dot-matrix printer, for example, the pattern of dots that forms the
individual characters is immediately obvious to the naked eye. This is because the dots are relatively
large and of a uniform size. On high-resolution laser printer output, however, the characters look
solid because the dots are much smaller and often can be of varying sizes.
Printer resolution is usually measured in dots per inch (dpi). This refers to the number of separate dots
the printer can produce in a straight line one inch long. Most printers function at the same resolution
both horizontally and vertically, so a specification such as 600dpi implies a 600-dot×600-dot one-inch
square. A 6666600dpi printer can therefore print 360,000 dots in a square inch of space. Some print-
ers, however, specify different resolutions in each direction, such as 720×1,440dpi, which means the
printer can produce more than one million dots(!) in one square inch (1,036,800 dots to be precise).
Despite improvements in monitor resolution, printer resolution has increased far more. Thus, the res-
olution of a printed page continues to be far higher than that of a typical PC monitor. The word reso-
lution is used to quantify PC video displays, too—usually in terms of the number of pixels, such as
800×600 or 1024×768. By print standards, however, the typical PC video display has a resolution of
only 72dpi–96dpi. By measuring the actual height and width of an image on your screen and compar-
ing it to the image’s dimensions in pixels, you can determine the dpi for your display.
See Chapter 15, “Video Hardware,” for more information about video display resolution.