| 摘要 |
A female creasing drum 20 features a central channel 30, and a pair of lateral ribs 26, projecting radially outwards relative to an adjacent outer surface 34 of the drum 20. The female drum 20 may be used in combination with a corresponding male drum (2,fig.4) to crease sheet material (14,fig.4). In an alternate embodiment the ribs 26 may be provided as part of an insert (fig.7). The crease provided by the female drum 20 may provide an improved fold, in which cracking of typeface on sheet material may be reduced. |
