An improved development station extends the useful life of toner in the housing and increases the number of images developed by the developer supply. The improved development station includes a toner supply for providing toner to a developer sump; a mixing auger for uniformly blending and charging toner particles supplied by the toner supply into the developer material; a magnetic roller for receiving the developer material and bringing the developer material into contact with a photoreceptive member, and a variable developer material restrictor for variably restricting flow of developer material to vary the mechanical stress delivered to the developer material.