抄録
The smoothness of paper ranks as one of the most important properties in the evaluation of its printability.
Several types of measurements, air flow, optical, friction, physical, electrical and others have been devised to measure the smoothness of paper.
A smoothness tester equipped with a vacuum air micrometer has been manufactured for trial in our laboratory and its performance test has been carried out. The vacuum air micrometer works well without a cell of constant pressure, and exhibits a high magnification.
A basic experiment on the measurement of roughness of metal surface has been performed with this instrument, and the data obtained has been indicated in a diagramatic manner. After necessarry conditions for nozzle, orifice and indicator were introduced from these diagrams, the instrument has been applied to the measurement of smoothness of paper. The experimental results may be summarized in the following way :
(1) This smoothness tester consists of a nozzle, a manometer, an orifice and a vacuum pump as is illustrated in Figure 3. Facility in handling is its special merit.
(2) Accuracy and reproducibility of the values obtained with this instrument areenough to use it as a smoothness tester.
(3) When the data provided by this instrument are plotted against the roughness of all kinds of paper surface, a linear relationship is obtained ; while when plotted against the data obtained with the Bekk Tester, a hyperbolic relationship is found to exist. For art papers, there is scarcely any relationship between the data those with the Bekk Tester.
(4) This tester differs from the Sheffield Smoothness Tester in mechanism of nozzle, type of indication, direction of air supply and values for papers of higher smoothness.
(5) A good correlation exists between the data with this instrument and those with the Densometer, when measuring the air resistance of paper.
