Many businesses and consumers choose laser printers for their printing needs. Though more expensive than common inkjet and dot matrix printers, the print quality from a laser printer is excellent. Laser printing is high contrast, easy to read, and permanent on most paper.

Laser printers do not use a laser to burn text and images onto the paper. Instead, they use an innovative application of static electricity to render the image and bond it permanently to the paper.

How they work
Laser printers are mechanically more complex when compared to inkjet or dot matrix printers. A typical laser printer has many key components that must all work together to print properly. The major parts of a laser printer include the paper tray, toner cartridge, drum assembly, corona wires, fuser, and feed rollers.

When printing signals are sent from a computer to the laser printer, many mechanical operations happen simultaneously. Inside the printer, a tiny laser beam (hence the name "laser printer") traces the image and text from the computer on a rotating drum that is sensitive to light. The areas that are hit by the laser beam become charged with static electricity. The next step is to make the toner, a heat-sensitive fine black powder, adhere to the traced image.

To accomplish this, paper is pulled from the paper tray into the printer by the feed rollers. It is next passed over the corona wire where it too is charged with static electricity-the opposite charge of the drum. The paper is rolled over the drum and the toner is transferred to the surface of the paper only on the areas traced by the laser. The paper, its surface now coated with toner, is passed through a very hot fuser where the toner is melted into the fibers of the paper. The feed rollers then send the printed paper out of the printer.

Choosing paper and toner
Unlike inkjet printers that are very sensitive to paper quality, most laser printers work well on all types of plain or "copy" paper (specialized "laser paper" is sold in most stores, but printing performance is often no better than printing on standard paper-with the exception of color printing). It is worth noting that laser printers are susceptible to jamming if the paper is too thick, creased, or wrinkled. Most laser printers cannot print directly on a CD-ROM, but they can print on transparency materials, labels, and envelopes.

The toner cartridge on a laser printer does not contain print heads; it merely serves as a reservoir for the toner. Print quality should not be affected by aftermarket or recycled toner cartridges, as long as they are quality direct-replacements, and designed for the specific printer. Most toner cartridges in laser printers last for several thousand pages of printing before a "low toner" indicator alarms, or print quality deteriorates.

The future of laser printers
The first laser printers were monochromatic (black ink only). These printers had just one toner cartridge, and the paper made but a single pass over the drum. Today, color laser printers have multiple toner cartridges and the paper makes multiple passes over the drum allowing them to print text, images, and photographs in full color.

With prices more than double that of inkjet or dot matrix printers, the quality of printing has always been high with a laser printer (even the most basic laser printer on the market today will deliver printing at 600 dots-per-inch), but shortcomings with graphics and photos always left the quality color and photograph printing to other technologies. Today's color laser printers offer impressive color and image rendition, but it is only a matter of time before the current 1200-dpi printers will be superseded by those with better resolution, and even lower pricing.