Variable force wide document belt transport system

In a document transport for transporting document sheets over a copier platen and into a registration position thereon for copying with a single, light reflective, flexible, unapertured and air impervious wide frictional movable belt providing a uniform light imaging background for the document sheet, the improvement comprising:

• selectably actuatable vacuum means for selectably applying a vacuum to vacuum plenum means overlying said vacuum belt above said platen,
• said vacuum means lifting all but selected minor areas of said belt away from said platen toward said vacuum plenum means when a vacuum is applied to said vacuum plenum means,
• said vacuum plenum means allowing said belt to drop from said vacuum plenum means into engagement with a document sheet on the platen over a much larger area of said belt when said vacuum is removed from said vacuum plenum means as compared to when said vacuum is applied to said vacuum plenum means, and
• belt deforming means for deforming said minor areas of said belt away from said vacuum plenum means towards said platen for selective area driving of a document sheet on the platen with said deformed minor areas of said belt when said vacuum is applied to said vacuum plenum means.