There are several other types of printers available, such as thermal dye printers (for printing photographs) and thermal printers (for creating mailing labels). But these are niche printer technologies. Our focus here is on printers designed for mainstream users.

Ink Jet Printers
Ink jet printers fall into three categories: three-color, four-color, and photo ink jets. The standard for ink jets is the four-color printer. The typical model holds two cartridges—one with black ink and one with color inks (cyan, magenta, and yellow). Some hold four cartridges, with a different one for each color, which means you don't have to throw out the unused ink in a tank just because you've used up all the yellow.

Three-color ink jets may soon disappear as the prices for four-color ink jets continue to drop. But you can still find a few representatives of this vanishing breed. Three-color ink jets are essentially the same as low-end four-color models, except that they can't hold both a tricolor cartridge and a black-ink cartridge (the fourth color) at the same time. Instead, you have to switch the cartridge to change between color and monochrome printing. Given the current prices of four-color ink jets, there's almost no reason to get a three-color ink jet.

The photo ink jet category isn't as clear-cut as the other two. Many four-color ink jets print photos at almost true photographic quality. And some printers that are labeled "photo ink jets" are simply four-color printers with one or two photo-friendly features added, such as the ability to plug in a digital camera directly to print photos. (See the sidebar "Photo Printers" for more on photography-related features.)

No matter what features a printer has, however, four-color printers are hampered by their gamut, or the range of colors they can produce. A printer's gamut depends on the inks used. Most photo ink jet printers expand their gamuts by using additional ink colors, usually light cyan and light magenta. And for most of these printers, photographic output is almost or completely indistinguishable from processed prints. Unfortunately, many photo ink jets are uncomfortably slow when printing text, so check out a photo printer's text speed before considering it as your only printer.

Laser Printers
A true laser printer uses a photosensitive drum or belt that picks up an electrostatic charge wherever the laser beam hits it. The charged areas then pick up toner and transfer the toner to paper. When most people refer to laser printers, however, they actually mean laser-class printers; some of the subcategories within laser printers use notably different technologies. What laser printers have in common is that even the slowest models print faster than almost any ink jet printer. As a rule, they also produce crisper lines and edges for text and graphics than do ink jets.

Laser printers fall into four categories: monochrome, four-pass color, single-pass color, and solid ink. The most popular category of laser-class printers, monochrome lasers, offer a level of crispness for text and lines that ink jet printers can't match without slowing to a crawl. It's getting harder to find a monochrome laser with a speed of less than 12 pages per minute (ppm). This category also includes LED and LCD printers. All three use light to draw the image of a page on a photosensitive drum or belt. The defining difference lies in the light source: laser, LED, or LCD.

Color laser printers—whether four pass or single pass—are for people who want the speed and text quality of a monochrome laser but need color, too. The best color lasers even print photographs as well as many ink jets, though no color laser that we've seen can match the true photo quality of the best photo ink jets.

Four-pass color lasers take at least four times as long to print in color as in black and white. A single laser beam draws a separate image for each of the four ink colors (cyan, magenta, yellow, and black), with the paper requiring a separate pass through the printer for each image. This four-pass design is now limited to older models and inexpensive low-end ones.

Single-pass color lasers are the standard today. Built around four internal lasers, this kind of printer draws images for all four colors at the same time. This lets it print all four images on a page with a single pass, so the speed for color printing is the same as for monochrome.

Keep in mind that with any color printer, you're basically printing four images—one for each color—which must be aligned, or registered. With single-pass lasers and LED printers, if the four print images don't line up properly the output displays faulty registration, causing blurry photos or visible gaps between sections of a pie chart. Misregistration is generally more of a problem with color LED printers than with color lasers.

Solid-ink printers start with a block of ink—usually wax or resin—which they melt and then spray either directly on a page or on a drum that rolls against one, as in an offset printing press. The drum approach tends to show better results, because it offers print speeds and output quality similar to a color laser's and produces more consistent color. A disadvantage is that the ink doesn't slide well over glass, which can cause paper jams in some office copiers.

Multifunction Printers
No matter what printer category you're interested in, you must also choose between a standalone printer and an all-in-one (AIO) device—the latest term for what is more commonly called a multifunction printer (MFP) or multifunction device.

At minimum, an MFP combines a printer and scanner to function as a printer, scanner, and copier. Most MFPs also have fax capability, either via software that lets you use your computer's fax modem or via built-in modems, letting you send faxes even when your computer is off. Some include document feeders as well, making it easier to scan and fax multipage documents.

The biggest argument against MFPs used to be that they made serious compromises in one or more functions. This is no longer the case, which is one reason they are becoming increasingly popular. The current MFPs combine high-quality scanners with the same engines you'll find in standalone printers. And they cost less than buying separate components. But you may not be able to find the exact mix of printer, scanner, copier, and fax features you want.

The tighter you are on desktop space and budget, the more seriously you should consider an MFP. The more particular you are in choosing a printer, scanner, copier, and fax—with specific features for each—the less likely you are to find an MFP that meets your needs.