摘要 |
An empty envelope assurance system is provided. The system includes a conveyor for conveying an opened envelope having a front face and a rear face along a path of movement. The conveyor is arranged such that any contents of the envelope rests against one of the front face or the rear face. A first sensor measures a thickness of the front face and any contents resting thereagainst, and generates a signal having a value indicative of the thickness. A second sensor measures a thickness of the rear face and any contents resting thereagainst, and generates a signal having a value indicative of the thickness. A signal processor receives the signals generated by the first sensor and the second sensor, and compares the values of the signals generated by the first sensor with the values of the signals generated by the second sensor to determine whether they correspond within a predetermined limit to determine whether the envelope contains any contents.
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