Abstract: A currency counter for counting currency notes withdrawn from a supply and advancing the notes one by one along a path past a density detector and a magnetic material detector to a stacker at a delivery location upon energization of a common drive motor in which an amplifier responsive to the density detector is automatically calibrated each time the counter starts and in which density and motor current signals are combined for doubles detection. The motor speed is adjusted for document length to provide a predetermined number of counts per minute. An adaptive counterfeit check is made. The motor is deenergized at the end of a batch count and momentarily reenergized to ensure that the last note of the batch is stacked.

Abstract: An improved audible alarm system for a document counter having an internal oscillator for producing a binary coded output in response to count signals applied to the counter in response to sheets moving along a path in which the counter internal oscillator is coupled to an audible alarm in response to a misfeed.

Abstract: Documents such as checks, food stamps or the like are successively advanced along a path between a transversely spaced pair of light-emitting diodes (LEDs) and a correspondingly spaced pair of photodiodes to generate signals for counting and misfeed detection. Various error detectors detect sheet misfeed by integrating signals derived from one or more sheet sensors and comparing the integrated signal with reference signals that vary with the drive speed. A doubles detector generates a signal indicating a double feed if the integral of an analog optical density while below a predetermined threshold lies beyond a predetermined limit. A potentiometer permits adjustment of the threshold optical density at which the integrator becomes operative. An LED coupled to the output of a spare amplifier on the chain note board permits detection of the momentary presence of an output signal from a particular error detector.

Abstract: Apparatus for counting and endorsing documents in which a motor drives respective pairs of feed rollers to move documents along a feed path from an input location and along the feed path to an output location. Movement of an endorser adjacent to the feed path from an inoperative position to an operative position reduces the motor excitation to cause the rollers to move the documents along the path at a slower rate.

Abstract: Apparatus for examining documents moved along a path between a light source normally energized at a first level and a photodetector, in which a first potential proportional to the long term average value of the photodetector output with no document between the light source and the photodetector and a second potential proportional to the instantaneous value of the photodetector output are compared to energize the light source at a higher level by shorting part of the resistance in the normal energizing circuit when the second potential falls below a predetermined percentage of the first potential.