This printer produces the best print quality. It is very quiet and it is the fastest. Example resolutions are 1200 x 1200 and 2400 x 1200. Example speeds are 16 and 20 ppm. The printer cartridge contains a photoconductive drum and a positively charged black powder (toner). The printer works as follows. First, the cartridge drum is positively charged. Then, as it rotates, a laser beam is used to negatively charge the drum dots that correspond to the pattern to be printed. This produces a negatively charged electrostatic image of that pattern. As the drum revolves, since the toner powder itself is positively charged, it clings to this electrostatic image producing a corresponding toner image of the pattern to be printed. Meanwhile, while coming from the input tray, the paper is covered with strong negative charges and then when passing by the drum it pulls the toner image away. Finally, on its way to the output tray, the paper is heated so as to melt the toner powder and this permanently fuses it into the paper. The laser printer is the most expensive but when printing so many pages its operational cost (cost of needed cartridges) is less than that of inkjet printers. |
