A replenishment and image mottle reduction system for adding carrier particles to a developer housing in a two-component developer toner imaging machine. The replenishment system includes (i) a carrier-only hopper for receiving and containing a first quantity of carrier particles; (ii) metering valves connected to a discharge end of the carrier-only hopper; (iii) a pneumatic plenum connected to the metering valves; (v) an air blower connected to the carrier-only hopper and to the pneumatic plenum for pressurizing the carrier-only hopper and for pneumatically conveying a metered quantity of carrier particles in an air stream from the pneumatic plenum; and (vi) a carrier separator assembly connected to the pneumatic plenum, located above each developer housing and including a carrier current collector, for separating fresh carrier from the air stream, and for allowing the carrier separated as such to drop by gravity into the developer housing.