rear stack support paddle for supporting the rear of a stack of flat articles;
a mechanical arm for positioning the cartridge, containing a stack of flat articles, at a cartridge receiving dock;
a cam for opening a door of said cartridge by means of relative movement between the cartridge and the cartridge receiving dock;
a hold bar insertable into the cartridge between the door and a front of the stack of articles for supporting the front of the stack to maintain a desired orientation of the stack;
a front finger positionable at the front of the stack of flat articles and a rear finger positionable at the rear of the stack;
a drive for moving the hold bar away from the stack prior to moving the stack of flat articles from the cartridge;
adrive for moving the front and rear fingers from the cartridge to move the stack of flat articles to a feeder station;
a feeder for feeding articles from a queued stack into a sorter having a plurality of output compartments, each output compartment having a cartridge therein;
a drive for moving said articles into a selected cartridge in one of the plurality of compartments;
a sweep gate for guiding articles into a cartridge as a stack of articles in the cartridge;
a sensor for when a cartridge should be removed from an output compartment;
a controller for disabling the movement of articles into the cartridge when the cartridge is to be removed from an output compartment;
an actuator for moving the sweep gate to a front of the stack;
a cam on the output compartment