Patent ID: 8333855

Claim:
A method for producing an envelope having improved seal integrity, the envelope having a flap and a body portion between which a seal is formed, the method comprising the steps of: applying a first conductive material to the flap of the envelope in an first area between the flap and the body portion of the envelope; applying a second conductive material to the body portion of the envelope in a second area between the body portion and flap of the envelope, the first and second areas being selected such that an end of the first conductive material contacts an end of the second conductive material when the conductive materials are arranged in a substantially common plane; sealing the flap to the body portion by closing the flap onto the body portion of the envelope and causing the conductive materials to lie in the substantially common plane; inspecting the sealing interface to determine whether the conductive materials exhibit a property of electrical continuity thereby confirming that a seal has been formed between the flap and body portion of the envelope, the step of inspecting the sealing interface including the steps of: (i) exposing the sealing interface to an electromagnetic field, and (ii) measuring the capacitance through the interface to determine whether the capacitance is between a threshold range of values indicative of a reliable seal.