Summary

8 IT Essentials: PC Harware and Software Companion GuideFigure 7-2Laser PrinterHow ToThe laser printer process involves six steps to print information on a single sheet of paper:Step 1.Step 2.Step 3.Step 4.Step 5.Cleaning: When an image has been deposited on the paper and fusion occurs,any remaining toner must be removed from the drum. A printer may have ablade that scrapes all excess toner from the drum. Some printers use AC voltageon a wire that removes the charge from the drum surface and allows the excesstoner to fall away from the drum. The excess toner is stored in a used-toner containerthat may be emptied or discarded.Conditioning: This step involves removing the old latent image from the drumand conditioning the drum for a new latent image. Conditioning is done by placinga special wire, grid, or roller that receives a negative charge of approximately–600 volts DC uniformly across the surface of the drum. The charged wire orgrid is called the primary corona wire. The roller is called a conditioning roller.Writing: The writing process involves scanning the photosensitive drum with thelaser beam. Every portion of the drum that is exposed to the light has the surfacecharge reduced to about –100 volts DC. This electrical charge has a lower negativecharge than the remainder of the drum. As the drum turns, an invisible latentimage is created on the drum.Developing: In the developing phase, the toner is applied to the latent image onthe drum. The toner is a negatively charged combination of plastic and metalparticles. A control blade holds the toner at a microscopic distance from thedrum. The toner then moves from the control blade to the more positivelycharged latent image on the drum.Transferring: In this step, the toner attached to the latent image is transferred tothe paper. The transfer, or secondary corona, places a positive charge on thepaper. Because the drum was charged negatively, the toner on the drum is attractedto the paper. The image is now on the paper and is held in place by the positivecharge.