1
U.S.T.H.B / C.E.I.L Unit 6
Computer science (L2) S2
1 Types of printer
A How many types of printer can you think of? Make a list.
B Read the article and then complete the table with the most relevant information.
Laser printers produce output at great speed and
with a very high resolution of 1,200 - 2,400 dpi.
They scan the image with a laser beam and
transfer it to paper with a special ink powder
called toner. They are constantly being improved.
In terms of speed and image quality, laser
printers are preferred by experts for various
reasons; for instance, they have a wider range of
scalable fonts than inkjets, can emulate different
language systems, and can produce high-quality
graphics; however, they are still expensive for
home users.
Thermal transfer printers are used to produce
colour images by transferring a wax-based ink
onto the paper. They are popular for printing bar
codes, labels and medium-resolution graphics.
Imagesetters produce very high-resolution
output (up to 3,540 dpi) on paper or on the actual
film for making the printing plates. In addition,
they are extremely fast. Imagesetters are most
often used in desktop publishing (DTP).
Although they produce the highest quality output,
they have one important disadvantage: they are
too expensive for homes or small offices.
In modern lithographic printing, images are
created on a DTP computer and then output
directly to the printing plates, without requiring
film as an intermediate step. This technology is
called computer to plate, or CTP, and the
machine used is called a platesetter.
Finally, we have plotters. Plotters use ink and
fine pens held in a carriage to draw very detailed
designs on paper. They are used for construction
plans, engineering drawings and other technical
illustrations. Nowadays, traditional plotters are
being replaced with wide-format inkjets.
Printing is the final stage in creating a
document. Since the results you can obtain
with different types of printer will vary
substantially, here is a guide to help you
decide which one is most suitable for your
needs.
To begin with, you should take into account
that printers vary in cost, speed, print quality,
and other factors such as noise or printing
method. Technology is evolving so quickly
that there is always a printer for every
application or need.
Dot-matrix printers use pins to print the dots
required to shape a character. They can print
text and graphics; however, they produce
relatively low resolution output – 72 to 180
dots per inch (dpi). They are used to print
multi-part forms, self-copying paper and
continuous-form labels. They are slower than
laser printers (see below) but much cheaper.
Inkjet printers operate by projecting small ink
droplets onto paper to form the required
image. Colour and hues are created by the
precise mixing of cyan, magenta, yellow and
black inks. Inkjets are fairly fast, quiet, and
not as expensive as laser printers.
Nevertheless, you can still expect high
quality results because there are some inkjet
printers on the market with a resolution of
2,400 dpi.
