Space efficient multi-sheet buffer module and modular printing system

A multi-sheet buffer module comprising:

• a frame having a bottom side and a top side opposite said bottom side;
• a first sheet transport path extending essentially vertically across said frame from a first sheet input port on said bottom side to a first sheet output port on said top side;
• a second sheet transport path parallel to said first sheet transport path, said second sheet transport path extending essentially vertically across said frame from a second sheet input port on said top side to a second sheet output port on said bottom side;
• and
• a plurality of sheet buffer paths extending essentially horizontally between said first sheet transport path and said second sheet transport path.

A printing system comprising:

• a first printing module;
• a second printing module;
• and
• a multi-sheet buffer module between said first printing module and said second printing module, said buffer module comprising:
• a frame having a first side adjacent said first printing module and a second side opposite said first side and adjacent said second printing module;
• a first sheet transport path extending across said frame from a first sheet input port on said first side to a first sheet output port on said second side;
• a second sheet transport path parallel to said first sheet transport path, said second sheet transport path extending across said frame from a second sheet input port on said second side to a second sheet output port on said first side;
• and
• a plurality of sheet buffer paths extending between said first sheet transport path and said second sheet transport path,
• said first sheet transport path receiving, at said first input port from said first printing module, a stream of sheets and feeding said stream of sheets out said first sheet output port into said second printing module,
• during said feeding of said stream out said first sheet output port by said first sheet transport path, at least one sheet buffer path diverting at least one selected sheet from said stream and holding said at least one selected sheet,
• said second sheet transport path receiving, at said second input port from said second printing module, said stream of sheets and feeding said stream out said second sheet output port into said first printing module, and
• during said feeding of said stream out said second sheet output port by said second sheet transport path, said at least one sheet buffer path feeding said at least one selected sheet into said second sheet transport path such that said at least one selected sheet is inserted into said stream at a predetermined point.

A printing system comprising:

• a first printing module;
• a second printing module stacked above said first printing module;
• and
• a multi-sheet buffer module between said first printing module and said second printing module, said buffer module comprising:
• a frame having a bottom side adjacent said first printing module and a top side adjacent said second printing module;
• a first sheet transport path extending essentially vertically across said frame from a first sheet input port on said bottom side to a first sheet output port on said top side;
• a second sheet transport path parallel to said first sheet transport path, said second sheet transport path extending essentially vertically across said frame from a second sheet input port on said top side to a second sheet output port on said bottom side;
• and
• a plurality of sheet buffer paths extending essentially horizontally between said first sheet transport path and said second sheet transport path,
• said first sheet transport path receiving, at said first input port from said first printing module, a stream of sheets and feeding said stream of sheets out said first sheet output port into said second printing module,
• during said feeding of said stream out said first sheet output port by said first sheet transport path, at least one sheet buffer path diverting at least one selected sheet from said stream and holding said at least one selected sheet,
• said second sheet transport path receiving, at said second input port from said second printing module, said stream of sheets and feeding said stream out said second sheet output port to said first printing module, and
• during said feeding of said stream out said second sheet output port by said second sheet transport path, said at least one sheet buffer path feeding said at least one selected sheet into said second sheet transport path such that said at least one selected sheet is inserted into said stream at a predetermined point.