The two primary technologies used in modern wide-format printers are LED and inkjet. LED printers are very similar to laser printers and copiers: they use a drum to transfer dry toner onto the print surface, and fuse the toner to the paper using heat. Wide-format printers use LEDs as the heat source instead of the lasers found in standard business printers.

Wide-format inkjet printers are functionally similar to their smaller cousins. They come in two basic varieties: thermal inkjets use heat to apply droplets of ink, piezoelectric inkjets use electrically-charged crystals instead. In both cases, the technology combines small dots of ink to create a wide range of colors.

Until recently, the most significant distinction between the LED and inkjet printers was that LED printers could be used as multifunction scanner/copiers in addition to printers, while inkjets could not. Now, some manufacturers are introducing upgradeable inkjet printers that can copy and scan, so this difference is becoming less important.

A new starting point in choosing between the two types is color. LED machines only print in monochrome; most inkjets offer color printing. This is the main reason LEDs are more common in AEC applications, while companies with graphics applications lean towards inkjets (see Choosing a wide-format printer for more).

Other differences between LED and inkjet printers are familiar to anyone who has evaluated standard business printers. For example, LED printers, like smaller laser printers, are generally faster than inkjets. Comparing speed can be tricky, though. Inkjets are often rated in square feet per hour, or the number of D size (24" by 36", a standard tech document size) prints per minute. LED printers are sometimes rated in linear feet per minute instead. Get the dealer to translate the speeds into the same measurements so you can easily compare.

The cost differences are similar to standard business printers, as well. LED printers are generally more expensive to purchase initially, but can make up for that difference with their lower overall cost per page. Inkjet printers are less costly to acquire, but can go through ink at a prodigious rate, driving up your cost per page.

Terminology
While it's not technically correct, many buyers use the terms "wide-format printers" and "plotters" interchangeably. Actually, no one makes plotters any more. The term "plotter" specifically refers to a machine that draws using a pen on a traveling arm. Improvements in inkjet and LED technologies have thankfully made these temperamental, expensive machines obsolete.

Some individual dealers and manufacturers use both terms, typically reserving the term "wide-format printer" for high-end graphics production machines — but in general, the two terms mostly overlap. "Grand format" printers are the extreme end of the spectrum — they print in widths from 5 to 16 feet or more.