Abstract
A novel apparatus for quantitative evaluation of a liquid, particularly, water absorption profile of paper was developed. The underlying principle for this method is similar to that of Bristow's method. This system is characterized by an applicator head with a small opening scanning a paper surface and by the detection system using an optical sensor pursuing the meniscus of water filled in a glass capillary connected with the applicator head. The level of sheet formation evidently affected the variation of water absorption rate profile, but the effect was observed only when the contact time was sufficiently long. The coefficient of variation for the worse formation was 36 % higher than that for the better formation at a contact time of 3 s, while it was almost the same at a contact time of 0.2s. However, no distinct correlation such as accordance of peaks was found between the transmitted light profile and the absorption rate profile. The density variation inducing pore size distribution near the surface layer may affect the absorption rate variation. Additionally, the influence of sizing degree was discussed. This novel system might be applied to clarify effects of water absorbency of basepaper on coating and adequate ink absorption in inkjet printing.
