On-line electrostatic defect detector for polyester base

摘要

A method and a device for detecting the presence of surface irregularities in a dielectric web, the web having an electrical surface charge. The device comprising a first electrical conductor (12) positioned close to the surface of the web (10) and extending across the width of the web (10) means for effecting relative movement between the first conductor (12) and the web (10) along the length of the web (10), thereby to induce a first electrical signal in the first conductor (12), and a detector responsive to the first electrical signal for detecting the high frequency components of the signal which are indicative of the presence of a surface irregularity in the web (10).