In a printing device, the conveying mechanism has a first path from a accommodating unit to the printing position and a second path that conveys the sheet that has once passed through the printing position to the printing position in an inverted state. Agents for dyeing keratin fibers, especially hair, based on a developer-coupler combination containing these compounds and methods of dyeing using these agents are described. The primary positive electrode comprises carbon dioxide and a means for electrochemically reducing the CO2. The exterior door is openablyclosably supported by the frame of the upper swiveling body. The magnetic conducting shell is coupled to the shaft and telescoped to the bushing. If the sending fails, the size of the keep-alive packet is iteratively changed to converge upon a path MTU, where the path MTU is the size of a largest keep-alive packet that can be sent from the first network device to the second network device without fragmentation.