Toner monitoring system for electrostatic copier

Claim 1

IN A COPYING MACHINE FOR SUBJECTING COPY MATERIAL TO THE ACTION OF A LIQUID DEVELOPER MADE UP TO TONER AND CARRIER FROM A SUPPLY OF DEVELOPER, A LIGHT SOURCE, A PHOTOSENSITIVE ELEMENT, MEANS MOUNTING SAID ELEMENT AND SAID LIGHT SOURCE IN SPACED RELATIONSHIP, MEANS FOR FLOWING DEVELOPER FROM SAID SUPPLY THROUGH THE SPACE BETWEEN SAID ELEMENT AND SAID LIGHT SURCE, MEANS FORMING A FIRST PASPASAGE WITH A RESTRICTION THEREIN, MEANS FOR FLOWING DEVELOPER FROM SAID DEVELOPER SUPPLY THROUGH SAID FIRST PASSAGE AND TO SAID SUPPLY, A SUPPLY OF LIQUID TONER, MEANS PROVIDING COMMUNICATION BETWEEN SAID TONER SUPPLY AND SAID FIRST PASSAGE ADJACENT SAID RESTRICTION, SECOND PASSAGE PROVIDING COMMUNICATION BETWEEN THE ATMOSPHERE AND SAID FIRST PASSAGE, AND ELECTRICAL CIRCUIT COMPRISING CLOSE SAID SECOND PASSAGE, AND ELECTRICAL CIRCUIT COMPRISING SAID LIGHT SOURCE AND SAID PHOTOSENSITIVE ELEMENT ADAPTED TO ACUTATE SAID SECOND PASSAGE CLOSING MEANS IN RESPONSE TO A PREDETERMED LOW TONER CONTENT OF SAID DEVELOPER, A SOURCE OF ELECTRICAL ENERGY, AN ORIGINAL TRANSPORT SYSTEM FOR CARRYING AN ORIGINAL ALONG A PREDETERMINED PATH THROUGH SAID MACHINE, A SENSOR DISPOSED ALONG SAID PATH TO BE ACTUATED BY AN ORIGINAL MOVING ALONG SAID PATH AND MEANS RESPONSIVE TO A PREDETERMINED NUMBER OF ACTUATIONS OF SAID SENSOR FOR COUPLING SAID SOURCE.