Laser printers are incredible inventions that have worked wonders for both individuals and businesses all over.
It all starts with your computer. Millions of bytes of data are streamed from the computer to the printer. There’s an electronic circuit inside the printer (which basically functions as a small computer) that analyzes the data and figures out how to print it so that it looks correct on the page. The electronic circuit activates a high-voltage wire called a corona wire that gives a static electric charge to anything nearby. The corona wire charges up a photoreceptor drum and the drum gains a positive charge spread uniformly across its surface.
Simultaneously, the circuit also activates the laser. The laser draws the image of the page onto the drum. But it doesn’t actually move in order to do this. Instead, it bounces off a moving mirror that scans it over the drum. The laser beam erases the positive charge where it hits the beam and creates an area of negative charge instead. Slowly, the image of the entire page builds up on the drum. There are areas with a positive charge where the page should be white and areas with a negative charge where the page should be black.
An ink roller touching the drum coats it with toner. The toner is given a positive electric charge, so it sticks to the parts of the drum that have a negative charge, since opposites attract. So now an inked image of the page builds up on the drum.
A sheet of paper from a hopper on the other side of the printer feeds up toward the drum. As it moves along, it’s given a strong positive charge by another corona wire. 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 now, the toner particles are resting lightly on the surface of the paper. The inked paper passes through two hot rollers, which make up the fuser unit. The heat and pressure from the rollers fuse the toner particles permanently onto the fibers of the paper.
Then out comes your document!
If you’re looking for a laser printer for yourself or for your company, take a look at QualPath’s selection.
Woodford, Chris. (2016). Laser printers. ExplainThatStuff!