Toner is a powder used in laser printers and photocopiers to form the printed text and images on the paper, in general with a toner cartridge. In its early form it was a mix of carbon powder, iron oxide, and sugar. Then, to improve the quality of the printout, carbon was melt-mixed with a polymer. Toner particles are melted by the heat of the fuser, and bound to the paper. In earlier machines, this low-cost carbon toner was poured by the user from a bottle into a reservoir in the machine.
Current machines feed directly from a sealed laser toner cartridge. Modern laser toner cartridges intended for use in color copiers and printers come in cyan, magenta, yellow and black (CMYK). Some toners are classified as UN 2807 Magnetized material while others present flammability. It is necessary to refer to the manufacturer’s Safety Data Sheet to ascertain safety.