Media conductivity measurement system
A system for measuring the conductivity of a flexible media positioned between a conductive backing and a conductive roller, wherein the conductive roller contacts the flexible media in a roller contact region. A pressure control mechanism presses the conductive roller against the second surface of the flexible media with a specified contact pressure, and a motion control system provide a relative motion between the conductive roller and the flexible media. A resistance measuring system connected to the conductive roller and the conductive backing measures the conductivity of the flexible media within the roller contact region. A data recording system records the measured conductivity of the media as a function of position.
1. A system for measuring the conductivity of a flexible media, comprising:
a conductive backing adapted to be positioned in contact with a first surface of the flexible media;
a conductive roller adapted to contact a second surface of the flexible media in a roller contact region when the flexible media is positioned between the conductive roller and the conductive backing;
a pressure control mechanism for pressing the conductive roller against the second surface of the flexible media with a specified contact pressure;
a motion control system adapted to provide a relative motion between the conductive roller and the flexible media;
a resistance measuring system electrically connected to the conductive roller and the conductive backing that measures an electrical resistance of the flexible media within the roller contact region; and
a data recording system for recording the measured resistance of the flexible media as a function of position as the motion control system provides the relative motion between the conductive roller and the flexible media.
2. The system of claim 1 , wherein the flexible media is a web of media.
3. The system of claim 1 , wherein the flexible media is a sheet of media.
4. The system of claim 1 , wherein the conductive backing is a rigid strip of metal or a thin sheet of metal affixed to a backing plate using a flexible adhesive.
5. The system of claim 4 , wherein the motion control system moves the conductive roller laterally across the second surface of the flexible media.
6. The system of claim 1 , wherein the conductive backing is a conductive backing roller, and wherein the conductive roller and the conductive backing roller are attached to a common frame.
7. The system of claim 6 , wherein the motion control system moves the flexible media laterally between the conductive roller and the conductive backing roller.
8. The system of claim 1 , wherein the pressure control mechanism includes a spring positioned to press the conductive roller against the flexible media.
9. The system of claim 8 , wherein the conductive roller is attached to a pivot arm mounted on a frame, the pivot arm being adapted to pivot around a pivot axis, and wherein the spring is attached between the frame and the pivot arm thereby applying a torque on the pivot arm that causes the conductive roller to be pressed against the flexible media.
10. The system of claim 1 , further including a lifting mechanism that lifts the conductive roller away from the second surface of the flexible media.
11. The system of claim 10 , further including a latch mechanism which engages when the lifting mechanism lifts the conductive roller away from the second surface of the flexible media, wherein the latch mechanism holds the conductive roller in a lifted position.
12. The system of claim 1 , wherein the electrical connection between the resistance measuring system and the conductive roller includes a metallic brush which is held in contact with an outer surface of the conductive roller.
13. The system of claim 1 , wherein the conductive roller includes:
a bearing mounting having a cylindrical inner surface; and
a self-aligning mechanism that enables the conductive roller to tilt so that an outer surface of the conductive roller conforms to the second surface of the flexible media, the self-aligning mechanism including:
a mounting bolt; and
a compliant ring positioned around the mounting bolt;
wherein an outer surface of the compliant ring contacts the cylindrical inner surface of the bearing mounting, and wherein a width of the compliant ring is less than a width of the conductive roller.
14. The system of claim 1 , wherein the roller contact region defines a linear shape having a length that corresponds to a cross-track width of the conductive roller to enable resistance measurements in a cross-track direction.
15. A system for measuring the electrical conductivity of a flexible media including one or more layers of material disposed over a conductive layer, comprising:
a backing adapted to be positioned in contact with a first surface of the flexible media;
a conductive roller adapted to contact a second surface of the flexible media in a roller contact region when the flexible media is positioned between the conductive roller and the backing;
a pressure control mechanism for pressing the conductive roller against the second surface of the flexible media with a specified contact pressure;
a motion control system adapted to provide a relative motion between the conductive roller and the flexible media;
a resistance measuring system electrically connected to the conductive roller and the conductive layer of the flexible media that measures the resistance of one or more layers of material disposed between the conductive layer in the flexible media and the second surface of the flexible media within the roller contact region; and
a data recording system for recording the measured resistance of the flexible media as a function of position as the motion control system provides the relative motion between the conductive roller and the flexible media.
16. A method for measuring an electrical conductivity of a flexible media, comprising:
positioning a conductive backing into contact with a first surface of the flexible media;
moving a conductive roller into contact with a second surface of the flexible media in a roller contact region so that the flexible media is positioned between the conductive roller and the conductive backing;
pressing the conductive roller against the second surface of the flexible media with a specified contact pressure;
moving one of the conductive roller or the flexible media relative to the other of the conductive roller or the flexible media;
electrically connecting a resistance measuring system to the conductive roller and the conductive backing;
measuring a resistance of the flexible media within the roller contact region; and
recording the measured resistance of the flexible media as a function of a position of the conductive roller relative to the second surface of the flexible media in response to the movement of the one of the conductive roller or the flexible media relative to the other of the conductive roller or the flexible media.