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Laser Printer
Laser printers belong to the category of non-impact printers, which means that the printing process does not involve touching the pages.
Below is a list of a laser printer's primary components:| 1. | Laser | | 2. | Deflection mirror | | 3. | Drum | | 4. | Toner | | | 5. | Fixation cylinders | | 6. | Cleaning unit |
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Laser printers work according to the following principle:
First, the cleaning unit (6) creates a negative charge in the drum.
Next, the laser (1) is projected onto the deflection mirror (2), which adjusts itself, so that the laser beam touches the drum at a location that will appear in black later on. The laser beam neutralises the charge.
The drum turns, and the neutralised areas move past the toner (4), which contains negatively charged colour particles (also known as toner).
The negatively charged areas repel the toner so that it adheres only to the neutralised areas.
Finally, the toner touches the paper, which was positively charged and thus attracts the toner.
At this point in the process, it is still possible to smudge the toner. That is why the fixation cylinders (5) roll and burn the toner onto the paper. The fixation cylinders are very hot (about 200° Celsius).
The printed page is now ready, while any toner that may have remained on the cylinder is removed and the cylinder is then recharged with a negative charge. This process occurs within the cleaning unit (6).
By now, however, so-called LEDs (light-emitting diodes) have come into use instead of a laser. LEDs project light onto the drum line by line.
The advantages of a laser printer are high printing speed (6-30 pages a minute) and the clean, crisp appearance of the printed image.
These days, laser printer prices are low enough that even private users can consider purchasing one. That is why laser printers are popular and widely used.
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