Method and apparatus for printing onto a continuously advancing web of work material

摘要

In an apparatus for printing on a web of work material continuously advanced in an X coordinate direction at a velocity vwx, at least one print head having a plurality of print elements arranged in a scanning array extending in the X direction is repetitively movable relative to the apparatus. The scanning array moves at a velocity va along a path that includes at least one scan segment and at least one repositioning segment. As the scanning array traverses the scan segment it has a first velocity component vax in the X direction, and a second velocity component vay in a Y direction perpendicular to the X direction. The first velocity component vax is equal to the velocity vwx so that the scanning array in traversing the scan segment, scans a swath on the web parallel to the Y direction, having a swath height hs. The velocity component vay is such that in the time taken for the array to move along the full extent of the scan segment the web advances a distance hw in the X direction that is less than hs. The array then travels along the repositioning segment such that prior or equal to a time taken for the web to advance a distance d=hs-hw the print head is positioned for movement along the scan segment, thereby causing successive swaths of the web scanned by the array to be positioned immediately adjacent to one another.