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How do Laser Printers Work?

Multifunction laser printer that can also scan, copy and fax.
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  • Written By: Mary McMahon
  • Edited By: O. Wallace
  • Last Modified Date: 13 September 2014
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Laser printers have become ubiquitous in the office and copying environment. The first was developed in 1971 by Xerox, and in 1977, it was brought to the commercial market. The rapid, crisp printing soon made these printers a popular choice for many consumers, although the internal workings of the printer remained mysterious to many. Because of the name, some consumers think that these devices use a laser actively on the paper in some way. In fact, they actually harness static electricity to print, although lasers do play a role in the printing process.

A print job begins when data from a computer is received by the printer, which sends it through a central controller, a small computer inside the printer. Many laser printers have a controller that is capable of handling several jobs at once, putting them in a queue and then printing them. This ability to handle multiple sets of data makes this type of printer quite popular. After the controller has determined what is going to be printed, the process begins.

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Inside the printer, there is a drum that holds an electric charge. Next to the drum is a transfer corona roller, which can negatively or positively charge the drum as needed, as well as a toner unit. In most laser printers, the drum starts out positively charged, although this process can also work in reverse. The controller manipulates a small laser to “write” on the drum with a negative charge, creating an electrostatic image.

Then, the drum is rolled through the toner, which is positively charged so that it will cling to the areas of negative charge on the printer drum. The printer feeds a piece of paper, which is given an even stronger negative charge by the transfer corona wire before being rolled past the drum. The electrostatic image on the drum will transfer to the paper, which is then discharged to prevent it from clinging to the drum. Then it is fed through a fuser, which heats the toner and causes it to bind with the fibers in the paper.

Meanwhile, the drum passes a discharge lamp, which will expose the entire surface of the drum and erase the electrostatic image. The transfer corona wire applies another positive charge, and the printer is ready for the next page or job.

Color laser printers work by performing multiple passes. Most printers have blue, red, and yellow ink, in addition to black, which can be combined to form any color. Some printers progressively lay the ink onto the drum so that the image will print with one pass of the paper, while others recirculate the paper multiple times to apply progressive layers of color. Large color printers sometimes have separate drum and toner assemblies for each color, with the paper passing each drum separately.

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Discuss this Article

anon306208
Post 13

@Golf07: The reasons you stated are exactly why you should have a laser printer instead of inkjet printer. You are throwing money away because you don't print often. I am currently using an inkjet and wish I had put the $100 down to buy a laser printer. In the long run, an inkjet will cost me more money then a laser printer.

John57
Post 12

I am looking at buying a refurbished laser printer for my small business. I want the benefits a laser printer provides, but have a small budget to work with right now. I am wondering if this is a wise idea or would I have nothing but problems with it and wish I had purchased a new one?

golf07
Post 11

I remember when Xerox first became popular and eventually became a common office word. When someone referred to a copy machine or a printer they often just called it a Xerox machine. You don't hear this word used very often anymore. We have a Brother laser printer in our office that has been there for quite some time.

When my dad was looking to buy a laser printer for his business he read a lot of laser printer reviews to figure out which one would be the most cost effective for him. Just like anything, there is a difference in quality, the cost of ink and how many pages you can get from one ink cartridge.

I just stick with an ink jet printer for my home office. I don't do very much printing and sometimes my ink cartridge dries out before I have barely even used it. I think laser printers are best for those who do a lot of printing and need for their copies to be high quality that look crisp and clear.

honeybees
Post 10
I don't know much about the mechanics of how a laser printer works, but I do know they work much better than an ink jet printer. I use one at my office and also have a personal laser printer to use at home.

The laser printer has much better quality than an inkjet and also prints at a faster speed. Some people think they are too expensive, but I think in the long run, a laser printer is more economical to use if you make a lot of copies on a regular basis.

sunshined
Post 9

@anon39921 -- My laser printer is clearly marked showing it is a laser printer. I think most printers have this stamped on them somewhere. If it doesn't, you should be able to get the model number off the printer and look it up online to see specifically what type of printer it is.

anon71023
Post 7

can we print fabric type material via laser printer? or what changes in printer can make this happen?

anon39921
Post 5

Can I know whether the printer is a laser printer or not?

anon34987
Post 4

When printing on pre-printed 3 checks per page sheets, my laser printer "shadows" the check number, bank info, etc. onto the next check. I changed the paper thickness, but it still does it. What is causing this and how can I stop it?

hjohns
Post 2

The resolution of a laser printer is determined by the capabilities of the laser and the controller within the printer. The cartridge holds the imaging components like the drum, corona, development, and toner materials.

anon3437
Post 1

Does a laser cartridge have a microchip built in to determine the resolution or ??

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