Electrostatic printing

Claim 1

AN ELECTROSTATIC PRINTING SYSTEM COMPRISING A HOLLOW CONTAINER HAVING AS THE BASE THEREOF A RELATIVELY NONCONDUCTIVE SCREEN HAVING APERTURES THERETHROUGH ARRANGED IN A DESIRED PRINTING PATTERN, A RELATIVELY CONDUCTIVE MEDIUM POSITIONED SPACED FROM SAID SCREEN AND ADJACENT ONE SIDE THEREOF, A MIXTURE OF POWDER PARTICLES AND CONDUCTIVE CARRIER PARTICLES WITHIN SAID CONTAINER, THE SIZE OF SAID POWDER PARTICLES BEING SMALLER THAN SAID SCREEN APERTURES TO PASS THERETHROUGH, THE SIZE OF SAID CARRIER PARTICLES BEING LARGER THAN SAID SCREEN APERTURES NOT TO PASS THERETHROUGH, MEANS FOR MOVING SAID CONTAINER FOR URGING SAID CONDUCTIVE CARRIER PARTICLES TOWARD THE OTHER SIDE OF SAID SCREEN FOR ENABLING SAID CONDUCTIVE CARRIER PARTICLES TO PUSH SAID POWDER PARTICLES THROUGH SAID SCREEN APERTURES, A SOURCE OF POTENTIAL, AND MEANS INCLUDING A WALL OF SAID CONTAINER FOR CONNECTING SAID SOURCE OF POTENTIAL BETWEEN SAID CONDUCTIVE CARRIER PARTICLES AND SAID CONDUCTIVE MEDIUM FOR ESTABLISHING AN ELECTRIC FIELD THEREBETWEEN TO CAUSE SAID POWDER PARTICLES TO TRANSFER TO SAID CONDUCTIVE MEDIUM.