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Unformatted text preview: n the paper placed in front of the print head.
To print a character, the printer selectively heats the appropriate set of nozzles as the print
head moves horizontally. An inkjet printer is shown in Figure 9.28. InkJet printers produce higher quality output than dot-matrix printers because they form
characters by very tiny ink dots. A high-resolution inkjet printer has as many as 64
nozzles within height of 7mm, providing print resolution of around 360 dots per inch.
Since inkjet printers produce printed output as patterns of tiny dots, they can print any
shape of characters that a programmer can describe. This allows the printer to print many
special characters, different sizes of print, and the ability to print graphics such as charts
InkJet printers are non-impact printers because they print by spraying ink on the paper.
Hence they are quiet in operation. However, like other non-impact printers, inkjet printers
cannot be used to produce multiple copies of a document in a single printing.
InkJet printers can be both monochrome and color. A monochrome inkjet printer uses a
single print head, whereas a color inkjet printer uses multiple print heads, one per color.
Color inkjet printers can produce multiple color output.
InkJet printers are slower than dot-matrix printers with speeds usually ranging between
40 to 300 characters per second. Typically, an inkjet printer is more expensive than a dotmatrix printer. They are preferred by individuals and organizations for generating printed
outputs if the speed of printing is not an important factor.
Drum printers are line printers that print one line at a time. The print mechanism of a
drum printer is shown in Figure 9.29. It consists of a solid cylindrical drum with
characters embossed (raised characters) on its surface in the form of circular bands. Each
band consists of all the printing characters supported by the printer in its character set and
the total number of bands is equal to the maximum number of characters (print positions)
that can be printed on a line. Thus a drum printer with 132 characters per line and
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- Spring '14