APPARATUS AND METHOD OF DETECTING THICKNESS OF SHEET DOCUMENT Russian patent published in 2014 - IPC G07D7/16 

FIELD: physics.

SUBSTANCE: apparatus has one detector unit, having a point of contact of a sheet document adjacent to a document transportation path and having a piezoelectric element, the first portion of which is fixed relative the document transportation path, wherein the piezoelectric element is assembled based on the condition that contact between the sheet document and the point of contact of the sheet document, as the sheet document passes the detector unit along the document transportation path, causes the second portion of the piezoelectric element to bend relative its first portion. A reading circuit is connected to the piezoelectric element to output an electrical signal based on a charge which depends on thickness of the sheet document generated by the piezoelectric element when it bends.

EFFECT: high accuracy of detection.

26 cl, 27 dwg