A special type of ink used by copy machines and laser printers. Toner consists of a dry, powdery substance that is electrically charged so that it adheres to a drum, plate, or piece of paper charged with the opposite polarity.
For most laser printers, the toner comes in a cartridge that you insert into the printer. When the cartridge is empty, you can replace it or have it refilled. Typically, you can print thousands of pages with a single cartridge.