Electrostatic printing system

Claim 1

IN AN ELECTROSTATIC PRINTING SYSTEM OF THE TYPE WHEREIN AN ARTICLE IS TO BE PRINTED ON WITH ELECTROSCOPIC POWDER PARTICLES, SAID ELECTROSTATIC PRINTING YSTEM HAVING MEANS FOR ESTABLISHING AN ELECTRIC FIELD WHEREIN SAID ARTICLE IS POSITIONED, SAID MEANS FOR ESTABLISHING AN ELECTRIC FIELD HAVING AS AN ELEMENT THEREOF A CONDUCTIVE APERTURED SCREEN WITH THE APERTURES ARRANGED IN THE FORM OF A PATTERN DESIRED TO BE PRINTED, SAID ARTICLES TO BE PRINTED ON HAVING ONE SIDE OPPOSITE TO AND SPACED FROM ONE SURFACE OF SAID SCREEN, AND SAID ELECTROSTATIC PRINTING SYSTEM ALSO INCLUDING A CONTAINER FOR SAID POWDER PARTICLES WITH SAID SCREEN CONSTITUTING ONE SIDE THEREOF, THE PARTICLES OF SAID POWDER BEING SMALLER THAN THE APERTURES OF SAID SCREEN AND HAVING TO BE PUSHED THERETHROUGH TO BE GUIDED BY SAID ELECTRIC FIELD TO SAID ARTICLE, THE IMPROVEMENT FOR PUSHING SAID POWDER PARTICLES THROUGH SAID SCREEN COMPRISING A MIXTURE WITHIN SAID CONTAINER OF A PLURALITY OF SOFT MAGNETIC PARTICLES AND ELECTROSCOPIC POWDER PARTICLES SUFFICIENT TO COVER THE PATTERN OF APERTURES OF SAID SCREEN, SAID MAGNETIC PARTICLES HAVING A PARTICLE SIZE LARGER THAN THE APERTURES OF SAID SCREEN SO AS NOT TO PASS THERETHROUGH, AND MEANS POSITIONED ADJACENT TO THE SIDE OF SAID ARTICLE WHICH IS NOT OPPOSITE TO SAID SCREEN FOR MAGNETICALLY ATTRACTING SAID MAGNETIC PARTICLES TOWARD SAID SCREEN OVER THE REGION OF SAID PATTERN OF APERTURES TO PUSH THOSE POWDER PARTICLES WHICH ARE BETWEEN SAID MAGNETIC PARTICLES AND SAID SCREEN THROUGH THE APERTURES IN SAID SCREEN.