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US 4,243,216 AGranted
Double document detection system
AssigneeNCR Canada Ltd - NCR Canada Ltee
InventorAli T. Mazumder
Life of this patent
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Abstract
A system for detecting the presence of more than one document along a path during the processing of the documents. A capacitance is introduced by the plural documents in contact with each other and wherein a delay signal is combined with an original signal to generate a multiple document detect signal for indicating the presence of the multiple documents.
Claims3
A double document detector comprising a
- conductive capacitor type sensing device operable for utilizing a document as the dielectric thereof and for generating a signal upon physically detecting a document,
- first R-C circuit means for introducing a capacitive delay in the generated signal due to the presence of one or more documents,
- AND gate means for comparing the generated signal with the delayed signal and generating an output signal,
- second R-C circuit means for introducing a capacitive delay in the output signal of said AND gate means to compensate for capacitance other than capacitance due to the presence of two or more documents, and
- inverter means receiving said delayed output signal from said AND gate means for generating a multiple document signal upon the presence of capacitive delay indicating that more than one document has been detected by said sensing device.
2 more elements
In a document handling apparatus, means for detecting the passage of double documents along a path comprising a
- conductive capacitor type sensing device operable for utilizing a document as the dielectric thereof and for generating a signal upon physically detecting a document,
- first R-C circuit means for introducing a delay in the generated signal due to the presence of a document,
- AND gate means for comparing the generated signal with the delayed signal and generating an output signal,
- second R-C circuit means for introducing a capacitive delay in the output signal of said AND gate means to compensate for capacitance other than capacitance due to the presence of two or more documents,
- and means receiving said delayed output signal from said AND gate means for generating a double document signal when said delayed output signal indicates that more than one document is detected by said sensing device.
2 more elements
A method of detecting double documents comprising the steps of:
- generating a signal upon physically detecting a document,
- introducing a capacitive delay in the generated signal due to presence of one or more documents,
- inverting the generated signal delayed due to presence of more than one document,
- comparing the generated signal with the delayed signal to generate and output signal,
- introducing a capacitive delay in the output signal to compensate for capacitance other than capacitance due to the presence of two or more documents, and
- generating a double document signal when the delayed output signal indicates that more than one document is detected.
3 more elements
Dependencies are inferred from the claim text.