Tamper detection and recovery

Claim 2

In a machine to which articles are fed at a regular time interval in succession, a detection apparatus comprising: means for sensing the condition when the article supply runs out and generating an out-of-article supply signal, and means for determining from the nature of the out-of-article supply signal whether the out-of-supply condition is actual or artifically induced.

Claim 3

The apparatus according to claim 1, including means for generating a first output signal when the out-of-article supply condition is actual and means for generating a second output signal when the out-of-article supply condition is artifically induced.

Claim 4

The apparatus according to claim 2, including means for interrupting the machine operation in response to said first output signal.

Claim 5

The apparatus according to claim 8, including means for cycling out and stopping the operation of the machine in response to said second output signal.

Claim 6

The apparatus according to claim 2, adapted for use in a machine for making copies on transfer sheets fed automatically from a sheet supply, the machine having means for setting it to make a predetermined number of copies in a copy run, means responsive to said first signal for interrupting the copy run operation of the machine, and means responsive said second signal for stopping and de-energizing the machine.

Claim 7

The apparatus according to claim 1, said determining means includes a first coincidence gate, a second coincidence gate, means for applying the out of article supply signal to said first and second coincidence gates, means for generating and applying a first train of pulses to said first coincidence gate wherein said first pulse train is synchronized to occur in succession at the rate at which the articles are fed and wherein the pulses of the first pulse train are timed so that, when the out-of-supply condition actually occurs and is detected, one of the pulses coincide at least in part with the out-of-supply signal occurring in response to the actual out-of-supply condition, and means for generating and applying a second train of pulses to said second coincidence gate wherein said second pulse train is synchronized to the rate at which the articles are fed but time displaced with respect to said first pulse train so that said second pulse train do not overlap with said first pulse train and wherein the pulses of the second pulse train are timed so that, when the artifically induced out-of-supply condition occurs and is detected, one of the pulses of the second pulse train coincide at least in part with the out-of-supply signal induced artifically, whereby said first coincidence gate detects the out-of-article supply signal indicative of the actual condition and said second coincidence gate detects artifically induced condition.

Claim 8

The apparatus according to claim 6, including means responsive to the output of said first coincidence gate for interrupting the operation of the machine so that the operation can be restarted after the articles are replenished, and means responsive to the output of said second coincidence gate for stopping the operation of the machine.

Claim 9

The apparatus according to claim 7, said second pulse train generating means is adopted to generate pulses having pulse width which is substantially wider than that of the first pulse train for enhancing the discrimination capability of said coincidence gate between the actual and artifically induced out-of-supply condition signals.

Claim 10

The apparatus according to claim 8, wherein said apparatus is adapted for use in a copier/duplicator machine wherein a tray is provided to hold a supply of transfer sheets, and said tray is positioned at a first location from which the sheets are fed automatically, and wherein said tray can be moved to a second positon to be filled with the supply, said sensing means is positioned to detect the paper being fed and is adapted to generate the out-of-supply signal when the last sheet of the supply is run out, and said sensing means also detecting the moving of said paper tray from said first position to said second position while the copy run of the copier/duplicator is in progress and generating the artifically induced out-of-supply signal.