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LASER SAFETY INTERLOCK Disclosure Number: IPCOM000022860D
Original Publication Date: 1976-Mar-31
Included in the Prior Art Database: 2004-Mar-27

Publishing Venue

Xerox Disclosure Journal


A laser safety interlock is provided whereby a light emitting diode 1 emits a light beam 2 in a given band to a photodetector 3, which is sensitive only to the band emitted by the diode, to maintain a solenoid in a shutter- open position out of the path of a laser beam. The diode and detector are located within an enclosure of a copying machine, The beam path between the diode and the photo- detector includes a reflector 4 located on a cover 5 for the enclosure, When the cover is removed, the reflector is also removed breaking the beam path between the detector and the diode whereby the solenoid is deactuated to allow a spring to return the shutter to a closed positions It is necessary that the photodetector be sensitive only to the band emitted by the diode since the detector will be exposed to other light when the cover is opens