Specifications

inkjet printing normally use an ink cartridge that also contains the print head, or, as in the case of
Canon BubbleJet printers, a removable and replaceable print head with a removable ink cartridge
insert.
Piezo Inkjet Printing
Piezo inkjet printing is a newer technology than thermal printing, and it presents distinct advantages.
Instead of heat, these printers apply an electric charge to piezo-electric crystals inside the cartridge
nozzles. These crystals change their shapes as a result of the electric current, forcing the ink out
through the nozzles.
Removing the high temperatures from the inkjet printing process presents two important advantages.
First, the selection of inks that can withstand 400° heat is very limited; piezo technology enables
printers to use ink formulations that are better suited to the printing process and less prone to smear-
ing, which is a traditional problem with inkjet printing. Second, spray nozzles that are not exposed to
extreme heat can last far longer than those traditional thermal cartridges. Epson pioneered the use of
piezo inkjet printing, and this method also is used by Lexmark.
Improving the Quality of Inkjet Printing
The early inkjet printers from companies such as Canon, Hewlett-Packard, and Epson could print at a
maximum resolution of only 300dpi–360dpi. Since the mid-1990s, though, resolutions have climbed
to 600dpi and beyond. Today’s cheapest inkjet printers typically have print resolutions of at least
600dpi–720dpi, and the newest high-performance printers feature resolutions as high as 2,400dpi, or
720dpi×2,880 for color printing.
Several developments have made these very visible improvements in print quality possible:
■ Improved ink nozzles. By reducing the size of the ink nozzles, a smaller dot is possible, improving
the look of both black text printing and color images. For example, Canon’s BJC-8200 intro-
duced a star-shaped nozzle capable of producing a truly round dot with more precise ink place-
ment to further improve print quality (see Figure 6). Some recent printers also use a staggered
two-column print head for each color, using one column of nozzles for lower-resolution photo
printing and adding the second column of nozzles for high-resolution printing by filling in the
gaps between the nozzles in the first column.
Figure 6 Canon’s BJC-8200 uses a star-shaped nozzle to improve the placement and shape of droplets for
improved resolution and better print quality.