TRAK is a mobile printing structure whose track is attached to the rear side of a laptop screen. It is easy to carry for business use when disassembled. The user just clips on the print head and prints an A4 sized document conveniently. The main objective was to create a light and slim printing accessory instead of the traditional laptop printer. Being reduced to the mere printing mechanism, TRAK provides a track to attach to the laptop and makes use of the “toy train” structure: A detachable cartridge moves along the track and can be removed and carried separately once the printing is done. TRAK is able to print the most common sized pages. The track is slim so that it fits on the laptop smoothly. Additionally, the cartridge can be stored in a laptop bag along with other accessories such as the mouse.