Capacitive Tape-Tension Sensor
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
The thickness of the air bearing between a web of material, such as a magnetic tape, and an air bearing guide can be measured by a capacitive sensor mounted in a slot in the web guide or in the magnetic head sensing the magnetic tape transitions. The capacitive sensor will measure the capacitance between the tape and the guide which is a function of the distance between the two. Capacitive sensors measure the tension of webs indirectly by measuring the thickness of the air bearing between the web and a metal plate, such as a web guide, or in the case of magnetic material, the magnetic head. The capacitive tension sensing is a non-contact method and has the advantage over a tension arm which must actually contact the web in order to determine the tension in the web.