Color xerography

Claim 1

A SINGLE STEP EXPOSURE METHOD OFOR THREE-COLOR XEROGRAPHY TO FORM IMAGES DEVELOPABLE WITH ELECTROSCOPIC MARKING MATERIAL COMPRISING POSITIONING IN CONTACTING LAMINAR CONFIGURATION FIRST A FIRST TRANSPARENT CONDUCTIVE ELECTRODE, SECOND A FIRST ELECTRICALLY INSULATING SHEET, THIRD A FIRST XEROGRAPHIC PLATE INCLUDING A TRANSPARENT CONDUCTIVE SUPPORT A FIRST PHOTOCONDUCTIVE INSULATING LAYER COATED ON ONE SURFACE OF SAID SUPPORT AND CONTACTING SAID FIRST INSULATING SHEET AND A SECOND PHOTOCONDUCTIVE INSULATING LAYER COATED ON THE OPPOSITE SIDE OF SAID TRANSPARENT SUPPORT MEMBER, FOURTH A SECOND ELECTRICALLY INSULATING SHEET CONTACTING SAID SECOND PHOTOCONDUCTIVE INSULATING LAYER, FIFTH A THIRD ELECTRICALLY INSULATING SHEET IN SURFACE CONTACT WITH SAID SECOND INSULATING SHEET, AND SIXTH A SECOND XEROGRAPHIC PLATE INCLUDING A CONDUCTIVE SUPPORT MEMBER AND A PHOTOCONDUCTIVE INSULATING LAYER COATED THEREON CONTACTING SAID THIRD INSULATING SHEET, SAID FIRST PHOTO-CONDUCTIVE LAYER BEING CONDUCTIVELY SENSITIVE TO LIGHT OF SUBSTANTIALLY ONLY A FIRST PRIMARY COLOR AND SUBSTANTIALLY TRANSPARENT TO LIGHT OF OTHER PRIMARY COLORS SAID SECOND PHOTOCONDUCTIVE INSULATING LAYER BEING CONDUCTIVELY SENSITIVE TO LIGHT OF A SECOND PRIMARY COLOR AND SUBSTANTIALLY TRANSPARENT TO LIGHT OF ATHIRD PRIMARY COLOR AND SAID THIRD PHOTO CONDUCTIVE INSULATING LAYER BEING CONDUCTIVELY SENSITIVE TO LIGHT OF A THIRD PRIMARY COLOR, APPLYING A VOLTAGE BETWEEN SAID TRANSPARENT CONDUCTIVE ELECTRODE AND THE TRANSPARENT CONDUCTIVE SUPPORT MEMBER OF THE FIRST XEROGRAPHIC PLATE AND BETWEEN SAID TRANSPARENT CONDUCTIVE SUPPORT MEMBER SAND THE SUPPORT MEMBER OF THE SECOND XEROGRAPHIC PLATE, AND PROJECTING A LIGHT IMAGE TO BE REPRODUCED ONTO SAID TRANSPARENT CONDUCTIVE ELECTRODE WHILE SAID VOLTAGES ARE MAINTAINED TO THEREBY FORM AN ELECTROSTATIC LATENT IMAGE CORRESPONDING TO A DIFFERENT PRIMARY COLOR ON EACH OF SAID THREE INSULATING SHEETS.