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PEER-REVIEWED ARTICLE
Fig. 5. Influence on overprint precision of different basis weights As shown in Fig. 5, a negligible overprinting error of 0.1 mm to 0.2 mm was observed for the paper with a basis weight of 60 g/m 2 to 70 g/m 2 , which resulted in greater precision and accuracy of overprint. As the basis weight increased to 90 g/m 2 , the overprinting error also increased, reaching to 0.72 mm. The increase was mainly attributed to the remarkable compression deformation and poor resilience during the overprinting process with the thickness increase of the paper in Z-direction. When the thickness could not be restored to the initial size under the action of rebound, a larger overprinting error occurred. Moreover, the overprinting error was related to the papermaking materials. The papers from hardwood exhibited superior performance in the overprinting (low overprint deviation), compared with that of softwood. The main reason for this result was that the hardwood contained more long and narrow micro-fibers. Therefore, the paper from hardwood had better printing performance and greater overprint accuracy. CONCLUSIONS 1. Compare to paper made from softwood, paper made from hardwood exhibited superior properties for the ink absorption capacity and overprinting precision, which was attributed to a greater content of fine fibers. 2. After beating, the void structure of the obtained paper became denser, resulting in decreased ink absorption capacity. 3. The increase of basis weight had a negligible effect on the ink absorption capacity.
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Dong et al . (2020 ). “Ink absorption and overprint,” B io R esources 15(1), 1397-1406.
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