Image processing of different sizes of document sheets in an electronic imaging system

In a document feeding and imaging system with a document input tray for sequentially feeding a set of plural document sheets loaded into said document input tray to a document imaging station with a document feeder having a sheet feeding path to be respectively imaged in said document imaging station with variable image processing conditions dependent on the size of said respective said document sheet, including a document sheet size measurement system for measuring at least one dimension of said document sheets, and wherein said document input tray has associated document size measurement sensors, wherein said set of plural document sheets loaded into said document input tray comprises a mixed size set of document sheets of different sheet sizes or a common size set of the same sheet sizes, the improvement comprising;

• an operator selectable input indicative of said mixed size set of document sheets,
• said operator selectable input providing a mixed size set control signal,
• said document feeder and said document sheet size measurement system being actuated by said mixed size set control signal to initiate a special prescan document size sensing operational mode,
• said special prescan document size sensing operational mode providing, as each said document sheet is fed by said document feeder to said document imaging station, sensing of the sheet size of that individual document sheet to obtain a document size signal without that document sheet then being imaged, and
• wherein in said same prescan document size sensing operational mode that individual document sheet is then automatically subsequently fed by said document feeder to said document imaging station to be imaged under said variably controlled image processing conditions,
• said variably controlled image processing conditions being controlled by said document size signal from said document sheet size measurement system for said imaging of that individual document sheet,
• and wherein if said operator selectable input indicative of said mixed size set of document sheets does not provide said mixed size set control signal, said document feeder and said document sheet size measurement system are actuated initiate a document imaging operational mode assuming said set of plural document sheets loaded into said document input tray comprises a common size set of the same sheet sizes.