Vacuum belt system having internal rotary valve

An apparatus comprising:

• a vacuum belt having belt perforations transporting sheets;
• a manifold adjacent said vacuum belt, said vacuum belt moves by said manifold, said manifold has manifold chambers, and each of said manifold chambers has manifold openings;
• vacuum lines connected to said manifold chambers, said vacuum lines exert vacuum force upon said manifold chambers, and said manifold openings exert said vacuum force through said belt perforations holding said sheets on said vacuum belt;
• and
• a cylindrical valve structure connected to said vacuum lines, said cylindrical valve structure comprises:
• a cylindrical sleeve having sleeve openings connected to said vacuum lines;
• and
• an internal valve cylinder positioned within said cylindrical sleeve,
• said internal valve cylinder has groups of vacuum slots comprising grooves in a rounded body of said internal valve cylinder,
• said vacuum slots have a reduced radius relative to said rounded body of said internal valve cylinder,
• said vacuum slots have slot lengths corresponding to lengths of said sheets on said vacuum belt,
• said internal valve cylinder rotates within said cylindrical sleeve in coordination with movement of said vacuum belt past said manifold, and
• said slot lengths limit supply of said vacuum force to only ones of said belt perforations where said sheets are held on said vacuum belt, and not between said sheets.

A printer comprising:

• a print head;
• a vacuum belt having belt perforations adjacent said print head, said vacuum belt moves past said print head to transport sheets past said print head, and said sheets is held on said vacuum belt by vacuum force exerted from said belt perforations;
• a manifold adjacent said vacuum belt, said vacuum belt moves between said manifold and said print head, said manifold has manifold chambers, and each of said manifold chambers has manifold openings;
• vacuum lines connected to said manifold chambers, said vacuum lines exert said vacuum force upon said manifold chambers, and said manifold openings exert said vacuum force through said belt perforations holding said sheets on said vacuum belt;
• and
• a cylindrical valve structure connected to said vacuum lines, said cylindrical valve structure comprises:
• a cylindrical sleeve having sleeve openings connected to said vacuum lines;
• and
• an internal valve cylinder positioned within said cylindrical sleeve,
• said internal valve cylinder has groups of vacuum slots comprising grooves in a rounded body of said internal valve cylinder,
• said vacuum slots have a reduced radius relative to said rounded body of said internal valve cylinder,
• said vacuum slots have slot lengths corresponding to lengths of said sheets on said vacuum belt,
• said internal valve cylinder rotates within said cylindrical sleeve in coordination with movement of said vacuum belt past said manifold, and
• said slot lengths limit supply of said vacuum force to only ones of said belt perforations where said sheets are held on said vacuum belt, and not between said sheets.

A method comprising:

• moving a vacuum belt having belt perforations past a print head to transport sheets past said print head, said sheets are held on said vacuum belt by vacuum force exerted from said belt perforations, said moving of said vacuum belt moves said vacuum belt by a manifold, said manifold has manifold chambers, each of said manifold chambers has manifold openings, vacuum lines are connected to said manifold chambers, said vacuum lines exert said vacuum force upon said manifold chambers, and said manifold openings exert said vacuum force through said belt perforations holding said sheets on said vacuum belt, a cylindrical sleeve has sleeve openings connected to said vacuum lines, an internal valve cylinder has groups of vacuum slots exerting said vacuum force upon said vacuum lines through said sleeve openings, said vacuum slots comprise grooves in a rounded body of said internal valve cylinder, said vacuum slots have a reduced radius relative to said rounded body of said internal valve cylinder, said vacuum slots have slot lengths corresponding to lengths of said sheets on said vacuum belt;
• and
• rotating said internal valve cylinder within said cylindrical sleeve in coordination with movement of said vacuum belt past said manifold,
• said slot lengths limit supply of said vacuum force to only ones of said belt perforations where said sheets are held on said vacuum belt, and not between said sheets.