METHOD AND APPARATUS FOR REPETITIVELY MARKING A MOVING SHEET

摘要

The energy of a laser beam is used to form images at intervals along a lengthwise moving web The images are formed along a plurality of axes spaced transversely of the web so that after slitting and cutting an image appears on each sheet. The laser beam is directed across the web and is repetitively and successively switched by notating optical mirrors in assemblies located at intervals across the web to scan image-bearing masks rotating with the mirrors. The beam impinges on respective mirrors of successive assemblies. The mirror assemblies are conical mirror segments or plane mirrors cooperating with a fixed conical mirror segment to produce a focussed line that is fixed in space and scans the rotating mask. The scanning line is re-imaged (90) on the web