depicts permanent magnets 60 arranged on the backing roll 4 as well as soft iron cores 61 with coils coordinated with the applicator roll 1 this embodiment compared to the one relative to fig8 has the advantage of being simpler and less expensive in design and that the adjustment of the application gap can be carried out more sensitively a quite significant embodiment is illustrated in fig1 here the distance a is electrothermally varied zonewise with the aid of induction coils 70 the advantage of this embodiment is that by means of the induction coils the spacing can be held extremely close namely at values of less than 100 mm additionally the induction current allows an extremely sensitive control making the zonewise control precise and reproducible this principle also can be provided anywhere in the flow path of the color coating thus the induction coils may serve to adjust the channel width between the applicator roll 1 and the trough 3 for example in the embodiment according to fig1 the zone control is again effected by means of temperature here the trough 3 is heated zonewise as viewed in the axial direction of the applicator roll 1 but may be heated differently as the case may be the heating may be performed with electrical heating rods by hot water steam by inductions coils or other means in the embodiment according to fig1 and 14 the steam heating concept is illustrated in more detail visible in the side elevation according to fig1 is a chamber 70 featuring a steam socket 71 with a valve 72 fig1 shows a number of.