Conductive brush paper position sensor
Patent 4641949 Issued on February 10, 1987. Estimated Expiration Date: 
August 26, 2005. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
August 26, 2005. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 2506454 2818252 2947917 3689143 3757164 Charge process with a carbon fiber brush electrode Recording sheet separating device in a transfer-type electronic copying machine Voice coil actuator registration system Transfer type electrostatic reproducing apparatus Paper guiding device in a copying apparatus Patent #: 4523754 InventorsAssigneeApplicationNo. 06/769515 filed on 08/26/1985US Classes:399/390, Having treatment of copy medium271/258.01, Responsive to sheet sensor399/389Having detection of size or typeExaminersPrimary: Prescott, A. C.Attorney, Agent or FirmInternational ClassesB65H 43/00 (20060101)B65H 43/02 (20060101) G03G 15/00 (20060101) AbstractThe present invention is concerned with a switching element comprised of oppositely disposed conductive fiber brushes and/or brush-like elements for detecting the presence or absence of paper at various locations in a xerographic copy machine. The oppositely disposed brushes are made from poly-acrylo-nitrile, a carbon based polymer material, which can be fabricated with relatively low values of resistance. Typical fiber bundles may consist of 6000 individual fibers each of 6-10 microns in diameter. In operation each individual conductive fiber acts as a separate electrical path through which the external circuit is completed. Passage of paper through the "nip" of the fiber to fiber electrical contact opens the circuit which is easily detected through associated circuitry which indicates the presence of paper. Likewise, arrays incorporating multiple such sensor switches may be fabricated for the purpose of indicating the size of the document interrupting specific low resistance fiber-fiber switches.Other References
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