How Does A Laser Printer Work?

In the last few years, lasers have become one of the most important tools human beings use. They are used in several different areas of work, including medicine. One of the uses has been in the development of efficient, high-quality ways to print documents. That’s why the laser printer got its recognizable name. A laser beam is one of a few key parts of the process in this type of printer. Using the laser gives these printers higher speed and excellent quality.

In basic terms, a laser is a device that sends a narrow, focused beam of high-intensity light. The term “laser” is actually an acronym that stands for light amplification by stimulated emission of radiation. Scientists who developed laser technology and work with it emphasize that laser light is different from other sources because of “coherency.” This means the laser light is directed in a focused beam or can be directed using special lenses.

In the printing process, the ability to focus and direct a narrow beam of light leads to precise (sharp) images. Once the information or data is sent from the computer to the printer, the laser printer converts the information into an image, including color if that is part of the data.

In the basic laser-print process, there is a drum or surface that is sensitive to light and is charged by electricity (negative charge). This is the point in the process where the laser beam does its work. The beam is tightly focused using lenses or mirrors and strikes the drum or photosensitive surface as directed by the data or information in the printer’s memory. When the laser beam contacts the drum in certain places (to produce the image or graphic) the negative charge changes to positive. This happens because the surface can’t hold a negative charge when affected by the light.

Basically, the places where the beam strikes the drum are the parts we see when the image is printed on paper. Toner or ink is placed on the drum or surface and it sticks to the places that have become positively charged from the laser beam. The toner or ink is transferred to paper to produce the text or image. This occurs using heat, pressure or a combination of both. (Toner is actually ink in a drier, powdered form.)

Laser printers differ from the long-used methods of “contact” printing in that no metal or other object actually contacts the drum or other surface. Laser printing is also quite different from the ink-jet method which shoots a tiny stream of ink onto certain areas. In fact, laser printing is much more like the old mimeograph machines that placed a sheet on a drum. The print was put on before the printing and the image was transferred to paper by a rotating surface. Of course, the laser process works differently because of the electrical charge and the use of a finely focused beam of light. While this is a very basic description of the laser printing process, it can give us some idea about the quality and efficiency of this type of printing.

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