Screen printing of half-tone pictures - uses projection housing offset from axis of drum to form projection paths of varying lengths

摘要

The projection housing (1) is offset from the axis (7, 11) of the film carrying drum (4) by an angle (ALPHA) which means that the projection paths (3) are of varying lengths around the film surface (5). An objective lens (8) is placed between the projection housing (1) and the film carrier. The image of the housing forms a stepped array of projection paths (13) along one edge of the drum.