A printer cartridge for electrographic printing (dry or liquid) is
provided with two chambers connected by a developer transportation system
that traverses a development zone in a first direction. As the toner
(developer) from a first of the two compartments is fed through the
development zone, excess or unused toner is transported by the developer
transportation system into a second of the two compartments. When the
first compartment has exhausted its supply of toner, there will be
sufficient toner captured in the second compartment to allow for printing
capability to be maintained in the system, without any replenishment. The
direction of flow of developer during printing is reversed from the
second compartment to the first compartment, passing through the
development zone.