Types of Laser Printers
Laser printers use a laser beam to produce an image on a photosensitive drum. Whenever light hits this photosensitive drum it creates an electrical charge that also creates an image. The drum is then rolled through a reservoir of toner that adheres to the electrically charged image. The image is then fused to the paper through heat and pressure. As laser printers print an entire page at a time as opposed to just segments of a page (as is true with other printers) they are sometimes called page printers.
To make things a bit confusing there are two types of printing machines called laser printers that do not have a laser inside them at all. One type uses an array of LED's to expose the photosensitive drum to enough light to replicate the image and the other uses LCDs to accomplish the same purpose. The printed pages these so-called laser printers are similar to the pages produced by machines that do contain lasers.
Laser printers are often classified by their potential to achieve a certain image resolution. The resolution is how many dots per inch (dpi) they can reproduce during a single printing. Resolutions range from 300 dpi at the low end to 1,200 dpi at the high end. By comparison, offset printing usually prints at 1,200 or 2,400 dpi.
You can also buy a color laser printer or a much more inexpensive standard monochrome laser printer. The standard monochrome laser printer uses a single toner and is a lot cheaper to operate in terms of printing expenses. By contrast color laser printers use four different colors of toner to print in full color. To put this in perspective, color laser printers tend to be about five to ten times as expensive as their monochrome siblings.
More About Laser Printers