Fujifilm EC103503 maintenance kit Quoted yield per cartridge up to 100000 pages * (approximate yield declared in accordance with ISO standard). The fuser is a major part of a laser printer that seals the print onto the paper medium. Heat is transferred through the toner by pressure of two rollers. One roller is heated and the other maintains pressure on the toner particles. The end result is the toner melting into the paper to form the printed image.