Method of electrostatic recording with different inkse

Claim 1

A METHOD OF RECORDING BY TWO DIFFERENT INKS COMPRISING THE STEPS OF: ESTABLISHING ON A CHARGE-RETENTIVE MEDIUM A PATTERN OF ELECTRIC CHARGES IN TWO DIFFERENT CHARGE DENSITIES OF THE SAME POLARITY, CORRESPONDING TO THE AREAS TO BE RECORDED BY THE SAID TWO DIFFERENT INKS; DEVELOPING THE SAID CHARGE PATTERN BY EXPOSING TO ITS ATTRACTIVE FORCES A FIRST UNCHARGED CONDUCTIVE INK CONSISTING OF PARTICLES OF SUCH SIZE AS TO BE ADHERENTLY ATTRACTED BY THE GREATER OF THE TWO SAID DIFFERENT CHARGE DENSITIES AND A SECOND UNCHARGED CONDUCTIVE INK CONSISTING OF PARTICLES OF SUCH SIZE AS TO BE ADHERENTLY ATTRACTED BY EITHER OF THE SAID TWO DIFFERENT CHARGE DENSITIES, SAID FIRST INK SIZE BEING OF THE ORDER OF NINETY TO ONE HUNDRED TWENTY MICRONS AVERAGE DIAMETER, SAID SECOND INK SIZE BEING OF THE ORDER OF TWENTY TO SIXTY MICRONS AVERAGE DIAMETER.