Plural belt document feeder

A document feeder for conveying document sheets into and away from an imaging position on a platen of a copier, including a vacuum belt transport system which comprises:

• a plurality of spaced-apart and unapertured belts moving between a white backing surface member and the platen, and
• a vacuum source for applying a partial vacuum to the inter-belt gap areas from beneath the belts to hold a document sheet against said belts so that the document is conveyed with the movement of the belts, characterized in that;
• said backing surface member is entirely planar in at least said inter-belt gap areas in said imaging position,
• multiple spaced protrusions which extend out from the backing surface member toward the platen are provided extending above the level of said plane of said backing surface member in said inter-belt gap areas at intervals on said backing member, beneath the belts, against which protrusions the belts ride to hold the belts spaced away from said backing surface member, the interstices between said protrusions providing openings to said inter-belt gaps from beneath the belts for said applying of partial vacuum to said inter-belt gaps, and wherein said protrusions are provided in mutually parallel rows extending in the direction of movement of the belts, with each belt riding on a respective pair of such rows of protrusions.