State advantages and disadvantages of laser printers

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What is a laser printer?

This is an electrostatic technology powered printer that uses  a laser beam of light to create characters on a piece of paper.

Laser Printer

How a laser printer works

1. Millions of bytes (characters) of data stream into the printer from your computer.
2. An electronic circuit in the printer (effectively, a small computer in its own right) figures out how to print this data so it looks correct on the page.
3. The electronic circuit activates the corona wire. This is a high-voltage wire that gives a static electric charge to anything nearby.
4. The corona wire charges up the photoreceptor drum so the drum gains a positive charge spread uniformly across its surface.
5. At the same time, the circuit activates the laser to make it draw the image of the page onto the drum. The laser beam doesn't actually move: it bounces off a moving mirror that scans it over the drum. Where the laser beam hits the drum, it erases the positive charge that was there and creates an area of negative charge instead. Gradually, an image of the entire page builds up on the drum: where the page should be white, there are areas with a positive charge; where the page should be black, there are areas of negative charge.
6. An ink roller touching the photoreceptor drum coats it with tiny particles of powdered ink (toner). The toner has been given a positive electrical charge, so it sticks to the parts of the photoreceptor drum that have a negative charge (remember that opposite electrical charges attract in the same way that opposite poles of a magnet attract). No ink is attracted to the parts of the drum that have a positive charge. An inked image of the page builds up on the drum.
7. A sheet of paper from a hopper on the other side of the printer feeds up toward the drum. As it moves along, the paper is given a strong positive electrical charge by another corona wire.
8. When the paper moves near the drum, its positive charge attracts the negatively charged toner particles away from the drum. The image is transferred from the drum onto the paper but, for the moment, the toner particles are just resting lightly on the paper's surface.
9. The inked paper passes through two hot rollers (the fuser unit). The heat and pressure from the rollers fuse the toner particles permanently into the fibers of the paper.
10. The printout emerges from the side of the copier. Thanks to the fuser unit, the paper is still warm. It's literally hot off the press!
    Source: EXPLAINTHATSTUFF!
    

​RELATED LINKS ..

• Differences between Printing Multiple Copies and Printing Multiple Pages
• Computer Studies Notes, Schemes, Lesson Plans, Practical Session and Syllabus

Advantages of laser printers

1. They produce neat  and high quality work
2. They are fast in printing
3. They are cheap to maintain
4. They can print back-to-back pages (both sides of the page automatically and sequentially)
5. They can print a series multiple pages
6. Don't make noise while printing
7. Can print both graphic and text
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Disadvantages of laser printers

1. They are expensive to acquire
2. They cannot produce multiple copies output
3. Their toner (ink gadget) is expensive to acquire
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