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2011-10-13

A+: Laser Printer Details

Toner in electrophotographic systems bears a negative charge, and paper (like most objects) has a positive charge.  The fusing system uses heat and pressure to fuse, or melt, toner onto the paper. The fuser roller is a Teflon-coated solid aluminum roller, heated by a halogen lamp.

Fusers run at 329-365 degrees Fahrenheit, hot enough to PAINFULLY burn you!

Another health risk is the ozone from older laser printers which us a corona wire, instead of a corona roller. Make sure to remove the ozone filter and dust it off outside when chnging your toner if you have one of those older printers.

The controller in the laser printer orchestrates all processes, especially turning the stream of data coming from a computer into a 'bitmap' of black and white areas so the black areas are covered with melted toner. More memory in the buffer of the controller speeds up the intake of the print job from the computer so the computer program can move on to the next page, print job or task.

The process, from start to finish, could be summarized as:  

Clean: Scrape the drum/belt clean, and illuminate it to eliminate charges.
Charge: Apply around 600 volts to the drum or belt.
Write: Laser scanning the drum drops the drum/belt to around 100 volts of charge.
Develop: Put toner on the drum or belt, it sticks to where the image should be.
Transfer: Move the toner to the paper.
Fuse: Melt the toner & mash it into the paper.

A mnemonic to help remember this is Charlie Can Walk, Dance, Talk French.


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