of the stroke element 2 an activating arrangement 8 is provided over the breadth of the machine in the form of a ledge which is attached to a lever arm 9 of a linkage 10 which is cyclically driven by a cam 11 via a drive lever 12 and a rod means 13 the fixed bearings 14 and 15 of the linkage 10 are attached to the carrier 1 the activating arrangement 8 operates together with latches 16 which are hinged to stroke elements 2 by hinges 17 and are biased in a clockwise direction by springs 18 these springs 18 are counteracted when the latch follows the activating arrangement 8 through its downward gravitational force every latch 16 can take up two positions namely an active position 34 a 34 wherein the activating arrangement 8 contacts a striker 19 on the latch and a non working position 34 b 34 in which the activating means 8 moves past the striker 19 as shown in fig2 in the active position 34 a 34 the activating arrangement 8 is coupled in a force transmitting manner with stroke element 2 via latch 16 so the former is moved into the working position of fig3 in the non working setting 34 b 34 per contra the stroke element 2 is not influenced thus remains in the at rest position of fig1 a block 20 is affixed to carrier 1 in which a plurality of control elements 21 in the form of single end fixed cantilevered piezoelectric transducers are held the control elements are controlled by electrical potential over conductors in a common cable 22 the cable 22 is provided with a plug 23 which provides a connection to a pattern forming control apparatus 24 by the application of potential the free end 25.