Charge measuring instrument for flexible materials

An apparatus for measuring triboelectric charge applied by a material to a flexible member, said material including a portion thereof in intimate contact with the member at a first position on an external surface of the member, comprising:

• a frame;
• a drum for mounting the member to an external periphery thereof, said drum rotatably mounted to said frame;
• a mechanism including a motor for rotating said drum, said mechanism operably associated with said drum;
• a support for supporting a material in intimate contact with the flexible member, so that the material and the sheet form a triboelectric charge on an external surface of the member;
• a charge measuring device operably associated with said drum for measuring an electrical field, said charge measuring device including a transducer operably associated with said drum for receiving an electrical field emanating from at least one of the material and the member and for transmitting a signal corresponding to said electrical field, a displaying device for displaying said signal, and an electrical conduit for transmitting said signal from said transducer to said displaying device;
• a tensioning device operably associated with said support for adjusting the tension between the material and the flexible member;
• a position measuring device operably associated with the material for accurately measuring the rotation of the material;
• and
• a controller for controlling at least one of said drum, said mechanism, said support, and said charge measuring device, wherein said mechanism is cooperable with said member to rotate the member to a position proximate said charge measuring device, and wherein the apparatus is adapted to measure the permittivity of the member by obtaining a first voltage measurement at the measured position, rotating the member using the drum for an elapsed time defining at least one complete revolution of the member, obtaining a second voltage measurement at the measured position, and utilizing the first voltage measurement, the second voltage measurement, and the elapsed time to calculate permittivity of the member.

A method for measuring a triboelectric charge applied to a flexible member, the method comprising:

• rotatably mounting a drum to a frame;
• mounting the member to an external periphery of the drum;
• mounting a support to the frame;
• mounting a material on the support so that the material is in intimate contact with the member;
• rotating the drum about an axis with the member and the material having relative motion therebetween defining at least one complete revolution of the member;
• and
• measuring the triboelectric charge applied to the periphery of the member resulting from the rubbing of the member with the material.