| 摘要 |
Lithographic imaging using non-ablative printing members combines the benefits of simple construction, the ability to utilize traditional metal ba se supports, and amenability to imaging with low-power lasers that need not impart ablati on- inducing energy levels. A representative printing member has a topmost layer that is ink-receptive and does not significantly absorb imaging radiation, a seco nd layer thereunder that is hydrophilic and does absorb imaging radiation, and a meta l substrate under the second layer. The printing member is selectively exposed to laser radiation in an imagewise pattern, and laser energy passes substantial ly unabsorbed through the first layer and is absorbed by the second layer. Heat builds up in the second layer sufficiently to detach the first layer, which is formulated to resist reattachment. But the first layer and, more significantly, the third layer act to dissipate heat from the second layer to prevent its at>lation. Where the printing member has received laser exposure-that is, where of the first and second layers have been detached-remnants of the first layer are readily removed to produc e a finished printing plate. |
