Xerographic development apparatus having a large reservoir for controlled flow through a narrow development zone

摘要

A novel development system for controlling the flow rate of developer through a narrow development zone, using a reservoir which has a feed chamber for maintaining a constant pressure head at the entrance to the narrow development zone. Developer flow is initiated upon demand by virtue of actuation of a valve positioned between the feed chamber and the entrance to the development zone; since considerable developer mixing occurs in the developer reservoir, mixing devices for mixing added toner with carrier beads may be simplified.