Typewriter

A typewriter comprising a carriage displaceable along a platen (1), a servo-motor (4) coupled to a motor shaft (3) for driving a device for selecting a character to be printed from the characters carried by a printing head disposed on the carriage, said motor shaft (3) being rotatable so as to occupy at least one angular rest position corresponding to the rest position of the printing head, a first gear train (5 to 9) including first and last controlled pinions driven by the motor shaft and a second gear train including first and second pinions (14,15) for driving the platen (1), said platen (1) co-operating with an angular ratchet device (13,40) retaining it in several angular positions, characterized in that the second pinion (15) of the second gear train (14,15) is secured to a transmission pinion (22) carried by a control member (25,26) adapted, during a platen driving order, to bring the transmission pinion (22) into engagement with said last controlled pinion (9) of the first gear train (5 to 9) when the platen (1) and the motor shaft (3) are immobile, said last controlled pinion mounted on a pivotal axis, the number of teeth of the pinions of the first gear train (5 to 9), and of the second gear train (14,15) provided in such a manner that, when the motor shaft (3) rotates from any one of said rest positions to another of said rest positions or to the same rest position and when the platen (1) rotates from any one of said angular positions to another of said angular positions, said last controlled pinion (9) and said transmission pinion (22) rotate through an angular displacement equal to an integer number of teeth, the cogging of the pinions being such that the teeth of the transmission pinion (22) always fit between the teeth of the last controlled pinion (9) during a platen driving order.