Drive for transporting and reversing an ink ribbon, and for withdrawing the printing head in printing devices

A printing device which includes:

• an ink ribbon, a printing head, a platen and means for transporting and reversing the transport direction of said ink ribbon and for withdrawing said printing head from said platen which comprises first and second gear wheels, a control shaft fixed to each of said gear wheels, first and second gear rings on reel holders disposed on the sides of said printing device, said gear wheels alternately engaging, by sliding of the control shaft in the longitudinal direction, one of said gear rings, said device further including a cord and guide rollers on said printing head, said cord being guided over said printing head via said guide rollers, the withdrawal of said printing head being effected by the tensioning of said cord, one of said gear wheels cooperating with said gear rings on said reel holders being coupled via a first pawl-and-ratchet device to a common drive shaft, said device further including a deflection lever and a cam mechanism which includes a cam disc, said cam disc being connected to said common drive shaft via a second pawl-and-ratchet device, said first and second pawl-and-ratchet devices being arranged to drive in opposite directions, and said common shaft being drivable in a reversible manner by means of a single electric motor.