Two-stage document singulating apparatus for a mail handling system

In a device for processing documents being transported therethrough along a document feed path, a singulating apparatus comprising:

• a first singulator having a first retard assembly and a first feed assembly disposed opposite to each other along the document feed path, the first retard assembly and the first feed assembly cooperating together on a stack of documents subject to a stack advance mechanism force and being transported along the document feed path and passing between the first feed assembly and the first retard assembly to separate and transport downstream along the document feed path individual documents from the stack of documents;
• and
• a second singulator, positioned downstream along the document feed path from the first singulator, having a second retard assembly and a second feed assembly disposed opposite to each other along the document feed path, and wherein at times when a plurality of documents from the stack of documents that are in overlapping relationship with each other pass through the first singulator without being separated and without being subject to the stack advance mechanism force and are received by the second singulator the second retard assembly and the second feed assembly cooperate together on the plurality of documents to separate and transport individual ones of the plurality of documents downstream along the document feed path.