Gao Gesellschaft Fur Automation Und Organisation Mbh

Gunter Pauli

Erwin Lob

Gerhard Jahn

Gunter Krause

The invention discloses a method and an apparatus for determining the condition or genuineness of flat articles, in particular bank-notes. The bank-note passes through a test station in which a large portion of its surface is scanned by a scanning system as it passes through. The electric signals generated by the scanning system are edited in an analyzing electronic circuit and compared with suitable limiting values and a signal denoting a faulty position is generated when a certain tolerance is exceeded. At least one surface portion defined in respect of position and size is selected and the electric signals appropriate to the scanning of this surface portion are compared only with limiting values selected for this portion. Thus, it is possible to check the condition and/or genuineness of flat articles, such as sheets of paper, securities, bank-notes and the like while the general rate of rejection and the exact analysis of preferred portions can be equally set alongside one another, without influencing one another, and examined.

Method and means for determining the state and/or genuineness of flat

The circuit arrangement includes a measuring device having an output circuit connected to one input of a comparator, and including a voltage divider whose tap is connected to the other input of the comparator. A storage capacitor is connected to the tap of the voltage divider and to such other input of the comparator and provides a reference voltage bearing a fixed relation to, but always lower than, the signal voltage of the measuring device in the quiescent state of the arrangement. A bias voltage may be applied to the tap of the voltage divider. When the measuring device responds to a test object, the voltages at the comparator inputs are so switched that the reference voltage is held above the signal voltage until the measuring device returns to the quiescent state. In the quiescent state, the signal voltage exceeds the reference voltage and the comparator, changing back to the zero state, restores the initial condition of the two voltages. A switching arrangement is provided which, when the reference voltage falls below a predetermined minimum value, and if the arrangement has not switched to the operating state, provides a corresponding logic signal.

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Grobenzell, Germany

Gunter Pauli