Experiments to Find On-line Measurements of the Structure of the Tissue Paper Surface

Sammanfattning: The structure of tissue paper has great influence on the quality of the resulting paper produced. One method of measuring the crepe wavelength on-line is sought in order to improve process control as well as to promote greater precision and uniform quality of the end product. In this study, a probe was used to read the surface of the paper whilst the paper travelled at a low speed. Light from a light emitting diode was emitted at a specific angle and collected at the corresponding reflecting angle, from the paper surface. Focusing the lenses at 45º angle produced results matching closest to the expected wavelength, and such measurements were made on a numerous commercial papers to validate the method. The collected signal contains a lot of information from the surface of the paper and from reflected signals inside the paper. The signal was processed using a mathematical approach to extract the most common wavelengths for each paper. The measured wavelength was found to closely match measurements made with commercial off-line equipment. This new method has a good initial potential to work on-line, however further investigation regarding the effects of high speeds upon the sampling still has to be carried out.