Abstract: An apparatus for the series production of Moebius ribbons comprises a threading robot having its four degrees of freedom (X,Y,Z,R). A second robot, movable in one direction, with two degrees of freedom (Z',R') is mounted on the first robot. The two robots cooperate to transfer between them a ribbon of delicate material, the ribbon being extracted from the ribbon cartridge and imparted with the 180.degree. twist required for the manufacturing of the Moebius ribbon.

Abstract: Known methods and devices for overlap-welding of printing by means of ultrasonics have been developed further to enable problem-free use, particularly with wire printers also having thin wires, and to enable welding of multi-color ribbons. The invention also permits more durable components. In the method according to the invention, the printing ribbon to be joined is retained in a non-overlapping fashion on movable plates, preferably by means of a vacuum, and is severed by a cutter, preferably by means of an ultrasonic sonotrode and cutting anvil, and is then moved so that the ribbon ends are in overlapping position, and then welded, preferably with a structured part of a sonotrode on a wielding anvil which is likewise structured. A device according to the invention has two plates with ribbon-retaining means, a cutter, and a joiner, such as a welder, for joining the two ribbons ends. The plates are movable to at least two positions suitable respectively for the cutting and joining functions of the machine.