Analysis and Measurement of the Imbibition Characteristic of Paper Based in the y-Direction

作者:Liu Guodong; Fu Sijia; Zhang Meiyun; Wang Yue
来源:49th Conference of the International-Circle-of-Educational-Institutes-for-Graphic-Arts-Technolo gy-and-Management / 8th China Academic Conference on Printing and Packaging, 2017-05-14 to 2017-05-16.
DOI:10.1007/978-981-10-7629-9_71

摘要

The transport of print fluids into the paper including x, y and z-directions is directly dependent on the imbibition characteristic of paper, and some common printing problems, such as print mottle, colour unevenness, and colour bleeding, are considered highly relevant with printing liquid uptake performance of paper. As the measurement of print fluid imbibition into the paper oriented in z-direction is extremely difficult in reality as the paper is too thin to be measured. However, the imbibition along the x and y-directions respectively, is a more practical solution since the wicking amount can be more easily measured. Therefore, in this paper we resort to imbibition measurement along the y-direction of paper to analysis imbibition dynamic of paper, imbibition mechanism oriented to y-direction, and further explore the possibility of replacing the z-direction imbibition of paper using y-direction imbibition. Considered the structural changes for samples, uncoated papers were filled to differing levels of 0, 0.75, 1.25 and 1.5% by weight using the technique of surface filling, to form a transition from the differential equivalent capillary radius. The imbibition characteristics of the paper then were measured with an accurate gravimetric balance system. Considering the classical imbibition dynamics of Lucas-Washburn, inertial and Bosanquet imbibition models for a common porous media, the measured imbibition performance was characterised with square root time (root t) and time (t), respectively. Therefore, the imbibition behaviour of papers was expressed using these two classical timescales and the analysed results are shown that the imbibition performance of uncoated unfilled paper oriented in the y-direction follows neither the classical Lucas-Washburn imbibition nor the Bosanquet imbibition, but associating with the surface wicking occurs rather via a surface film flow along the paper fibres leaving large voids initially empty. However, by adding more filler into paper, the imbibition dynamic can be reverted to Bosanquet imbibition model since the filler load in the surface layer of the paper, the imbibition dynamic is seen to revert to the Bosanquet imbibition model since the filler disrupts the fibre wicking arising from the reduction in permeability and the filling effect into the large voids, thus forming new finer pores by particle packing and aggregation. These findings enable a controlled design of imbibition properties when modifying the pore structure using high surface filled paper.

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