Tripartite developer for electrostatic images

Claim 1

A TRIPARTITE DEVELOPER FOR ELECTROSTATIC LATENT IMAGES COMPRISING A FIRST COMPONENT CONSTITUTED BY MIXTURE COMPRISING A FIRST COMPONENT CONSTITUTED BY LOOSE, MOVABLE PARTICLES OF ELECTROSTATICALLY-ATTRACTABLE TONER POWDER, A SECOND COMPONENT CONSTITUTED BY GRANULAR CARRIER MATERIAL COMPOSED OF LOOSE PARTICLES, EACH PARTICLE OF SAID SECOND COMPONENT INCLUDING A CORE AND A COATING BONDED THERETO AND EACH PARTICLE OF SAID SECOND COMPONENT HAVING A TRIBOELECTRIC RELATIONSHIP OF OPPOSITE POLARITY TO THE TONER POWDER, AND A THIRD COMPONENT CONSTITUTED BY A POWDER COMPOSED OF PARTICLES HAVING A RESISTIVITY IN POWDEER CFORM OF NO GREATER THAN LEAD ACETATE AND HAVING A TRIBOELECTRIC RELATIONSHIP WHICH IS STRONGLY NEGATIVE RELATIVE TO SAID CARRIER MATERIAL, SAID FIRST COPONENT COMPRISING PARTICLES IN THE SIZE RANGE OF FROM 0.1 TO 20 MICRONS, SAID SECOND COMPONENT COMPRISING PARTICLES IN THE SIZE RANGE OF FROM 30 TO 200 MESH AND SAID THIRD COMPONENT BEING OF AN INTERMEDIATE SIZE RANGE BETWEEN SAID FIRST AND SAID SECOND COMPONENTS, AND SAID THIRD COMPONENT BEING ADDED TO A PROPER XEROGRAPHIC DEVELOPOER MIXTURE OF SAID FIRST AND SAID SECOND COMPONENT IN THE RATIO RANGE OF FROM 1 PART OF SAID THIRD COMPONENT TO 3 TO 10 PARTS OF SAID FIRST COMPONENT.