HP 507A Yellow Original LaserJet Toner Cartridge

Laser printers and copiers not only need toner (ink powder) for printing, but also a drum (comparable with the print head of an inkjet printer). The drum puts the toner in the right place, and afterwards the paper is heated so the toner melts and is attached permanently to the paper. Drums, like all components of a printer, wear and will have to be replaced at some time, although they are fairly durable.