| 摘要 |
Device for detecting faults, such as carbon granules, smudges, and/or other dark areas on the end of cigarette filters, including sources of light energy for casting light on a cigarette filter being inspected, photocells positioned for individually scanning the filter tips as the cigarettes travel on a conveyor through an inspection zone, and a detection circuit for producing a floating reference signal which is derived from the highest repeating signal levels from normal filter tips previously inspected. The detection circuit compares the instantaneous signals produced from the photocells with the floating reference signal in a manner whereby the dark area, resulting from a fault such as a carbon particle, when scanned by the photocells will produce an instantaneous sensing signal differing from the floating reference signal so as to indicate the presence of a fault. The detection circuit automatically compensates for variations in color and texture of the filter tip material that could otherwise cause detection failure when utilizing a fixed type of reference. According to a further embodiment, the detection circuit includes an amplifier-filter section having a frequency response characteristic which enables the device to detect the smaller size faults with substantially the same ease as the relatively larger size faults. |
