| 摘要 |
A freshly printed continuously traveling paper web leaves a heated print drying zone hot with its printing dry enough to avoid smudging but retaining a residual amount of the printing ink's solvent oil which continues to vaporize, forming a boundary layer of vaporizing oil traveling with the web. For cooling, the web wraps partially around one or more cooling rolls where condensation can cause the vapor boundary layer to condense on the exposed cold roll surface to a liquid phase, exerting a solvent action more or less resoftening the otherwise adequately dried printing with consequent smudging on the roll surface. To prevent this, the boundary layer is pneumatically removed from either this exposed surface of the roll not contacted by the web, or from the web itself, preventing resoftening of the printing by what would otherwise be liquid solvent oil.
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