Do you know why a Xerox machine is called a Photocopier?
Actually, that is what it should be called. Xerox was the first company (or probably one of the first) which brought photocopier machines to the market and so even today some of us call them Xerox machines!
But do you know how they work?
It’s a very interesting machine. And it uses simple physical phenomena like Reflection of Light and Attraction between unlike Charges (yes, static electricity). Read up on the Internet or if you’re feeling plain lazy, just check this link: http://home.howstuffworks.com/photocopier1.htm