(57) A printer is provided with a print feed mechanism comprising supply and take-up spools
15 and 16 which have associated rotary motor induction coils which are energised with
alternating currents in such measure as to effect spooling and tensioning of the ribbon
14 during its transport past the printing head 13. A device 20 is provided for incrementally
advancing the ribbon 14 in discrete steps. The device 20 comprises two pairs of ribbon-engaging
elements, each pair defining a respective nip through which the ribbon passes, with
one element of each pair being movable along the path of the ribbon relative to the
other to advance the ribbon. The two movable elements are mounted on a common support
member and have associated therewith respective coils which cause the movements of
the support member. Printing takes place along successive bands of the ribbon which
extend along the ribbon and are disposed in side-by-side relation across the ribbon
width. When the ribbon is fully advanced in one direction, the direction of ribbon
transport is reversed and printing then takes place with the next band. The alternating
currents are regulated according to the relative quantity of ribbon on the two spools.
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