Samsung SU513A yellow toner Cartridge Quoted yield per cartridge up to 3500 pages * (approximate yield declared in accordance with ISO standard). Toner cartridges are a container of toner powder holding the print medium material for the modern laser printer. Toner powder is a dry powder that is used to form images, including pictures and text on sheet of paper. This is achieved by electrostatically charging and heating the toner, after being spread on the paper. The heating process melts the toner powder into the paper and it then becomes part of the paper medium. The whole process is assisted by two rollers (fuser) which compacts and presses the toner into the paper. This is why the finished paper is warm when a print is completed. Printing with a laser printer is very precise and sharp in the definition. This is one of the great advantages of laser printing.