Electrostatic printing apparatus

Claim 1

APPARATUS FOR APPLYING LIQUID DEVELOPER COMPOSITION TO A CONTINUOUS WEB BEARING A LATENT ELECTROSTATIC IMAGE, SAID APPARATUS COMPRISING A PAIR OF PRESSURE ROLLERS ADAPTED TO CONTACT OPPOSITE SURFACES OF SAID WEB, ONE OF SAID ROLLERS BEING ADAPTED TO HAVE SAID WEB CONTACT A SUBSTANTIAL PORTION OF THE PERIPHERY THEREOF, THE OTHER OF SAID ROLLERS BEING POSITIONED IN A PLANE ABOVE SAID ONE ROLLER SO AS TO INTAKE SUBSTANTIALLY LINE CONTACT WITH SAID WEB, DRIVE MEANS FOR ROTATING SAID ROLLERS TO MOVE SAID WEB THEREBETWEEN, MEANS FOR WASHING SAID OTHER ROLLER WITH SAID LIQUID DEVELOPER COMPOSITION TO SUBSTANTIALLY OBLITERATE OFFSET IMAGES FORMED ON SAID OTHER ROLLER AS A RESULT OF PREVIOUS DEVELOPMENT OF ELECTROSTATIC IMAGES ON SAID WEB WITH SAID OTHER ROLLER, ROTATION OF SAID OTHER ROLLER PROVIDING MEANS FOR CARRYING DEVELOPER COMPOSITION INTO CONTACT WITH SAID IMAGE BEARING WEB AND FORMING A TURBULENT NIP OF DEVELOPER COMPOSITION BETWEEN SAID IMAGE BEARING WEB AND THE SAID OTHER ROLLER, AND SUMP MEANS FOR COLLECTING DEVELOPER COMPOSITION FLOWING DOWN OVER THE SURFACE OF SAID IMAGE BEARING WEB ON SAID PORTION OF SAID ONE ROLLER.