Fractal dimension analysis of surface roughness of coated paper

The smoothness of coated paper for the high end printing materials would be one of the most important properties for the print quality. In this study, the surface of paper was measured with stylus by 2,000 to 20,000 data. Using these data, the FD values of thickness and friction mean deviation were obtained through the JMP program. The optimal conditions for measurement of the coated papers surface were surveyed by varying the load on the stylus and the number of data derived. FD values were measured to analyze surface characteristics such as roughness and smoothness of coated paper. The larger the number of data derived, the more detailed the measurement was possible, and it gave lower fractal value. Proper pressure on paper and measuring distance of stylus in order to differentiate hill and crater of paper surface were important. 5 gf stylus pressure and 20,000 data were proper among various conditions. FD values of base paper and coated paper were 1.30-1.36 and 1.19-1.29 respectively, and the results showed the smoothness of coated paper was improved by coating process. © 2019 Korean Technical Assoc. of the Pulp and Paper Industry. All rights reserved.