| 摘要 |
<p>PROBLEM TO BE SOLVED: To evaluate whiteness degree of an unknown specimen by a method wherein a fineness distribution of residual ink including residual ink of which average particle diameter is smaller than a specific value of that of a pulp or a paper, is obtained beforehand and a mutual relation contribution rate that each particle diameter number of the residual ink affects the whiteness degree, is obtained. SOLUTION: Only residual ink and colored particles are extracted from a fetched image and a diameter of a quasi-circle is calculated from the area and a fineness distribution of the residual ink and colored particles in a prescribed visual field area is obtained. The measurement is applied to ink scavenged pulp or pulp before ink scavenging treatment, for example, about 5-50 times, then the fineness distribution in a desired fineness range is obtained. The contribution rate with respect to an optical property of a particle diameter by each range of the particle size distribution is calculated in accordance with a linear processing. For example, particle size distributions of the residual ink of which diameters are smaller than 2μm and the ink of which diameters are not smaller than 2μm are obtained and the contribution rate of each particle diameter with respect to each optical property is calculated so that the optical property such as a whiteness degree and a darkness is evaluated only by measuring the particle size distribution of the residual ink.</p> |
