(L). Laser Printing:

Information can also be impressed on a light beam by modulating the laser itself. The laser printer (Fig.30) in computer systems uses a modulated semiconductor laser and the principle of xerography. The laser light is focused and scanned across a selenium drum where it photo activates electrostatic charges, which hold the carbon particles of the toner. Rotating paper over this drum under heat causes the toner to stick to the paper, forming the printing.

Figure 30. : Schematic diagram of a photoconductive drum assembly used in a laser printer

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