| 摘要 |
<p>The lay mark control system for sheet alignment for colour printing, uses a circle (2) with four arms (3) of a cross projecting radially outwards, forming the mark for one sheet. The other sheet uses four arms of a cross, having a size which will fit within the circle. Each arm consists of four parallel stripes in one design, or three parallel stripes ir a second design. The two sets of arms are brought into alignment. The field formed by the second sets of arms has a pattern width of between 10 and 200 lines preferably between 30 and 70 lines per centimeter.</p> |
