A pair of ultrasound sensors are mounted in the ADF, one below the original feed path (emitter) and the other above the path (receiver).
- When the original passes between the sensors, an ultra-sound wave from the emitter sensor below passes through the paper to the receiver above.
- The receiver converts the signal generated by the vibration of the signal against the paper to an electrical pulse and checks its level.
- If a double feed occurs, the space between the sheets will generate a lower signal. When the emitter detects this lower signal (lower than that of a single sheet) the machine issues Jam Code J099 (double-feed detected) and then original feed stops.
This double feed detection will not function with originals that have:
- Folds, wrinkles, tears
- Holes
- Imperfectly fused images
- Perforations
- Taped connections
- Taped surfaces
Feeding such originals could cause false detection of double-feeds.
Double-feed detection can be switched by the operator with an operator setting: Operator Adjustment > 1. Main: Image Position Adjustment > 0108 ADF Double Feed Detection Operation (On (default), Off).
The service technician must switch double-feed detection off/on with SP6040-001 [0 to 1/1/1] (Default 1: On) after installing the optional double-feed kit.