PLATEN DOCUMENT TRANSPORT SHOW-AROUND DELETION
Original Publication Date: 1982-Feb-28
Included in the Prior Art Database: 2004-Apr-03
Xerox Disclosure Journal
Many existing original document transports have a common flaw - "show-around". For example, over-platen document transport vacuum belts, or foam wheels all can print out (image) distinctive markings on the copy sheet if the copy paper is larger than the original, or if optical reduction is used and the document image is smaller than the copy. These markings may appear as ?ebra stripes" from multiple belts, or shadows from vacuum holes in a vacuum belt or wheel wells. Various techniques have been suggested to eliminate show-around, including shutters behind the foam wheels or measuring the document length as the document is fed (by the trail edge passing a sensor on its way onto the platen) and also measuring the copy paper length and appropriately turning on the inter-document erase lamp at the trail edge of the document image. However, the latter does not solve the problem in a manual copying mode, where the operator manually places the original on the platen. The disclosed system solves the problem in both the auto feed mode and manual mode with a sensor to detect the document trail/edge on the platen as the document is being imaged.