06/01/2018
A printer is a device that accepts text and
graphic output from a computer and
transfers the information to paper, usually
to standard size sheets of paper. Printers
vary in size, speed, sophistication, and
cost. In general, more expensive printers
are used for higher-resolution color
printing.
Personal computer printers can be
distinguished as impact or non-impact
printers. Early impact printers worked
something like an automatic typewriter,
with a key striking an inked impression on
paper for each printed character . The dot-
matrix printer was a popular low-cost
personal computer printer. It's an impact
printer that strikes the paper a line at a
time. The best-known non-impact
printers are the inkjet printer, of which
several makes of low-cost color printers
are an example, and the laser printer . The
inkjet sprays ink from an ink cartridge at
very close range to the paper as it rolls
by. The laser printer uses a laser beam
reflected from a mirror to attract ink
(called toner ) to selected paper areas as
a sheet rolls over a drum.
The four printer qualities of most interest
to most users are:
Color: Color is important for users
who need to print pages for
presentations or maps and other
pages where color is part of the
information. Color printers can also
be set to print only in black-and-
white. Color printers are more
expensive to operate since they use
two ink cartridges (one color and one
black ink) that need to be replaced
after a certain number of pages.
Users who don't have a specific need
for color and who print a lot of pages
will find a black-and-white printer
cheaper to operate.
Resolution: Printer resolution (the
sharpness of text and images on
paper) is usually measured in dots
per inch ( dpi). Most inexpensive
printers provide sufficient resolution
for most purposes at 600 dpi.
Speed: If you do much printing, the
speed of the printer becomes
important. Inexpensive printers print
only about 3 to 6 sheets per minute.
Color printing is slower. More
exp