Modular multifunctional mailbox unit with interchangeable sub-modules

In a mailbox module with sheet transport paths for separately collecting the print job sheets outputted by a shared user printer and selectably separating and feeding said print jobs of respective users into a superposed array of plural descrete mailbox print job sheet collection trays, the improvement wherein:

• said mailbox module has left and right side printer job output sheet inputs,
• said mailbox module has at least one vertically modular replaceable sub-module,
• said mailbox module has both a right side generally vertical sheet transport input path, and a left side generally vertical sheet transport input path, for sequentially feeding sheets respectively from said left or right side sheet inputs vertically to said replaceable sub-module,
• said mailbox module has a third generally vertical sheet transport path from said replaceable sub-module past said array of plural mailbox print job sheet collection trays to provide a tray selection path;
• and
• said replaceable mailbox sub-module comprising at least one interchangeable sheet processing apparatus connecting between said mailbox sub-module sheet transport input paths and said third sheet transport path to form a part of said mailbox module sheet path;
• said sheet processing apparatus operating on sheets in said mailbox sub-module prior to said separating and feeding of print job sheets into said mailbox print job sheet collection trays;
• wherein a sheet stacking elevator and a selectable plurality of mailbox bins are removably mounted to said mailbox module to be selectably fed said printer output sheets by said third vertical sheet transport passing thereby.