Printer sheet vacuum transport curled sheets acquisition

Abstract

The transporting of flimsy print media sheets having curled sheet edges being fed from a fuser or other input onto a vacuum sheet transport belt system is provided with improved acquisition by simultaneously blowing the upper surface of the sheet's curled lead edge area down towards the vacuum belt transport with a positive pressure airflow while the vacuum sheet transport is attracting the sheet with its an underlying vacuum manifold airflow. Both the vacuum manifold airflow and the positive pressure airflow may be respectively provided solely by the air intake and the air exhaust from a single blower. The positive pressure airflow may be provided from a manifold extending transversely over at least the upstream end of the vacuum belt transport, spaced therefrom, and feeding air to one or more air jets.

What is claimed is:  
     
         1 . In a sheet transport system with a sheet feeding path for transporting flimsy print media sheets having upper and lower surfaces, at lease some of which flimsy print media sheets in said sheet transport system are curled, said sheet transport system including at least one vacuum sheet transport system and at least one non-vacuum sheet transport system; wherein said vacuum sheet transport system has a vacuum blower providing a vacuum airflow to said vacuum sheet transport system for providing vacuum attraction of the lower surface of said sheets against said vacuum sheet transport system, and wherein said vacuum blower has a positive air pressure exhaust airflow output corresponding to said vacuum airflow; wherein a positive air pressure airflow system is provided and positioned to direct positive pressure air flow against at least a portion of the upper surface of said flimsy print media sheets being fed in said sheet transport system to blow said curled towards said sheet feeding path.  
     
     
         2 . The sheet transport system of  claim 1 , wherein said positive air pressure airflow system providing a positive air pressure against said flimsy print media sheets is provided by said exhaust airflow output of said vacuum blower.  
     
     
         3 . The sheet transport system of  claim 1 , wherein said non-vacuum sheet transport system is a fuser imparting curl to at least some of said flimsy print media sheets, which curled print media sheets are being fed towards said vacuum sheet transport system, and wherein said positive air pressure airflow system providing a positive air pressure against said flimsy print media sheets is blowing said sheets towards said vacuum sheet transport system to assist in the engagement of said curled print media sheets by said vacuum sheet transport system.  
     
     
         4 . The sheet transport system of  claim 1 , wherein said positive air pressure airflow system includes a positive air pressure manifold extending transversely over at least one end of said vacuum sheet transport system, spaced therefrom and feeding positive air pressure air to one or more air jets providing positive pressure air flow towards at least the leading edge area of said flimsy print media sheets being fed onto said vacuum sheet transport system.  
     
     
         5 . In a sheet transport system with a sheet feeding path for transporting flimsy print media sheets having a tendency for curled sheet edges downstream in said sheet feeding path, said sheet transport system including a downstream pneumatic vacuum sheet transport system and an upstream non-vacuum sheet transport system feeding said curled edge sheets onto said downstream pneumatic vacuum sheet transport system; wherein said downstream pneumatic vacuum sheet transport system has a pneumatic vacuum source with a vacuum airflow input to said downstream pneumatic vacuum sheet transport system for providing vacuum attraction of said sheets against said downstream pneumatic vacuum sheet transport system, and wherein said pneumatic vacuum source has a positive air pressure exhaust airflow output system corresponding to said vacuum airflow input, and wherein said positive air pressure exhaust airflow output system is positioned to direct positive pressure air flow towards at least the upstream edge of said downstream pneumatic vacuum sheet transport system and towards a curled sheet edge being fed onto said downstream pneumatic vacuum sheet transport system by said upstream non-vacuum sheet transport system, to blow said curled sheet edge towards vacuum engagement with said downstream pneumatic vacuum sheet transport system.  
     
     
         6 . The sheet transport system of  claim 5 , wherein said upstream non-vacuum sheet transport system is a xerographic thermal roll fuser imparting curl to said flimsy print media sheets.  
     
     
         7 . A method of transporting flimsy print media sheets having curled sheet edges comprising feeding said curled sheets out over a vacuum sheet transport belt system and attracting the sheet there towards with an underlying vacuum manifold airflow and simultaneously blowing the upper surface of the sheet down towards said vacuum belt transport with a positive pressure airflow, wherein both said vacuum manifold airflow and said positive pressure airflow applied to the upper surface of the sheet are respectively provided solely by the air intake and the air exhaust from a single air blower.  
     
     
         8 . The method of transporting flimsy print media sheets having curled sheet edges of  claim 7 , wherein said positive pressure airflow is provided from a positive air pressure manifold extending transversely over at least the upstream end of said vacuum sheet transport belt system, spaced therefrom, which positive air pressure manifold is feeding air to one or more air jets providing said positive pressure air flow towards at least the curled sheet edge being fed out over said vacuum sheet transport belt system.