The Microline 591 letter-quality printer anticipates and conforms to all your paper-handling needs. The difference is OKISMART Paper Handling, a unique patented technology that allows the ML 591 to "read and learn" the paper you feed it, then set the head gap to the optimum distance for best print quality. It also means less time to load and reload paper stock, and can lead to longer printer life. The ML591 delivers perfect output on letterheads, card stock, forms with up to 5 parts, and labels. And, unlike ordinary printers, the ML591 takes on envelopes like any other paper media. Just feed them into the printer and they emerge flawlessly printed, with no jams or smears. A patented sensor built into the ML591 printhead calculates the precise time and impact needed to print each dot, virtually eliminating uneven printing. The shape of each dot is more consistent, producing smooth, characters and stunning graphics. There are no gaps, no smears or light spots, regardless of paper type used. You get the professional look you want for every application, the printhead lasts longer, and the printer works quieter and uses less power.