Method of controlling contrast in a xerographic reproduction process

Claim 1

THE METHOD OF CONTROLLING CONTRAST IN A XEROGRAPHIC REPRODUCTION PROCESS WHEREIN A XEROGRAPHIC PLATE IS CHARGED, EXPOSED TO A PATTERN OF LIGHT AND SHADOW TO PRODUCE A LATENT CHARGE PATTERN AND DEVELOPED IN PROPORTION TO THE AMOUNT BY WHICH THE LOCAL POTENTIAL V OF THE ELECTROSTATIC CHARGE PATTERN IS LESS STHAN A FIXED BIAS POTENTIAL ON A DEVELOPMENT ELECTRODE, SAID METHOD COMPRISING APPLYING A CHARGING POTENTIAL VO, GREATER THAN SAID FIXED BIAS POTENTIAL, AND EXPOSING THE PLATE TO A PATTERN OF LIGHT AND SHADOW UNTIL SUBSTANTIALLY ALL AREAS THEREOF ARE REDUCED TO A POTENTIAL BELOW SAID FIXED IAS POTENTIAL WHEREBY THE SAID LOCAL POTENTIAL V REMAINING AT ANY GIVEN POINT ON THE PLATE, AFTER SAID EXPOSURE IS GEOVERNED BY THE EXPRESSION $-$=KE WHERE E IS THE SAID EXPOSURE AT THE SAID GIVEN POINT AND K IS A CONSTANT WHICH IS A FUNCTION OF SAID PLATE, SAID VO BEING CHOSEN SO THAT THE SAID REMAINING LOCAL POTENTIAL V WILL VARY FROM POINT TO POINT WITHIN A RANGE OF VALUES CORRESPONDING TO A DESIRED CONTRAST RANGE IN THE DEVELOPED PLATE, AND POSITIONING SAID DEVELOPMENT ELECTRODE ADJACENT TO THE DEVELOPABLE SURFACE OF SAID PLATE FOR DEVELOPMENT.

Claim 2

THE METHOD OF CONTROLLING CONTRAST IN A XEROGRAPHIC REPRODUCTION PROCESS WHEREIN A XEROGRAPHIC PLATE IS CHARGED, EXPOSED TO A PATTERN OF LIGHT AND SHADOW TO PRODUCE A LATENT CHARGE PATTERN AND DEVELOPED IN PROPORTION TO THE AMOUNT BY WHICH THE LOCAL POTENTIAL V OF THE ELECTROSTATIC CHARGE PATTERN IS LESS STHAN A FIXED BIAS POTENTIAL ON A DEVELOPMENT ELECTRODE, SAID METHOD COMPRISING APPLYING A CHARGING POTENTIAL VO, GREATER THAN SAID FIXED BIAS POTENTIAL, AND EXPOSING THE PLATE TO A PATTERN OF LIGHT AND SHADOW UNTIL SUBSTANTIALLY ALL AREAS THEREOF ARE REDUCED TO A POTENTIAL BELOW SAID FIXED IAS POTENTIAL WHEREBY THE SAID LOCAL POTENTIAL V REMAINING AT ANY GIVEN POINT ON THE PLATE, AFTER SAID EXPOSURE IS GEOVERNED BY THE EXPRESSION $-$=KE WHERE E IS THE SAID EXPOSURE AT THE SAID GIVEN POINT AND K IS A CONSTANT WHICH IS A FUNCTION OF SAID PLATE, SAID VO BEING CHOSEN SO THAT THE SAID REMAINING LOCAL POTENTIAL V WILL VARY FROM POINT TO POINT WITHIN A RANGE OF VALUES CORRESPONDING TO A DESIRED CONTRAST RANGE IN THE DEVELOPED PLATE, AND POSITIONING SAID DEVELOPMENT ELECTRODE ADJACENT TO THE DEVELOPABLE SURFACE OF SAID PLATE FOR DEVELOPMENT.