Modular loose leaf binder system and a binder ring used therein

A modular loose leaf binder system, comprising:

• a plurality of loose leaf paper sheets having opposing edges, each sheet having a plurality of aligned die-cut perforations proximate one edge thereof, and a predetermined distance from the perforation to said one edge;
• at least two modular binder rings for binding said plurality of loose leaf paper sheets, each of said rings including a disk-shaped central portion having a first axial width, an aperture formed substantially in the center of said central portion, and an annular outer rim having an arcuately shaped outer surface configured as an outer segment of a circle, said annular outer rim having a second axial width greater than said first axial width, said outer rim intersecting with said central portion defining an elbow, with a radial distance extending from said aperture to said elbow being greater than the predetermined distance from the perforations to the edge of said paper sheets;
• and
• a loose leaf cover having opposing edges and a plurality of die cut perforations proximate one said edge, said perforations extending a predetermined distance from said one edge less than the radial distance from the aperture to the elbow of said binder ring, said cover including a folding base portion opposite the perforated edge.