Monitoring corona discharge treatment of plastic sheet is achieved by non-contact field strength measurement, in conjunction with electrodes discharging and re-charging it

摘要

After leaving the corona discharge treatment plant, electrostatic behavior of the substrate surface is determined by continuous measurement of its electrical characteristics. An Independent claim is included for corona treatment plant, monitored as described. Preferred features: The field from the substrate (5) is measured with a non-contact, electrostatic induction field strength meter (11, 12, 13). The surface is first discharged at an electrode. It is then deliberately re-charged by a second electrode. The electrostatic behavior is determined from the electrostatic surface discharge rate. Before determination, the surface is given a defined charge from a electrode. Electrostatic characteristics are determined before and after charging in the plant. The difference is a function of treatment received.