by projecting and retracting parts of the surfaces of the forme cylinders

Full Title

Duplicating or printing apparatus or machines for office or other commercial purposes, of special types or for particular purposes and not otherwise provided for (addressographs B41L45/00) > for printing from selected parts of one or more printing surfaces in one cycle, e.g. line printing (by inking selected areas B41L27/20) > with co-operating forme and impression cylinders > by projecting and retracting parts of the surfaces of the forme cylinders