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Original Publication Date: 1983-Feb-28
Included in the Prior Art Database: 2004-Apr-04

Publishing Venue

Xerox Disclosure Journal


In an electrophotographic printing machine, copy sheets are advanced to and from the various processing stations on a sheet transport, indicated generally by the reference numeral 10. As shown in the drawing, sheet transport 10 includes a plurality of spaced endless belts 12 entrained about a pair of opposed spaced rollers 14 and 16. One of the rollers, e.g., roller 14, is driven by a motor (not shown) to move belts 12. The other roller, e.g., roller 16, is an idIer and rotates freely. Each belt 12 has a metal strip 18 in juxtaposition therewith. Strips 18 have one end thereof mounted pivotably on the transport frame with the other end being free. Preferably, strips 18 are shaped in the form of skis. The copy sheet is arranged to be interposed between strips 18 and belts 12. An electromagnet 20 is disposed interiorly of belts 18. Inasmuch as strips 18 are ferromagnetic, the normal force exerted on the copy sheet depends upon the magnetic attraction between electro-magnet 20 and strips 18. The magnetic attraction between electromagnet 20 and strips 18 varies as a function of the current exciting electromagnet 20. Yence, the normal force may be optimized for various weight copy sheets by selecting the appropriate excitation current for electromagnet 20. In the event of a copy sheet jam or printing machine malfunction, electromagnet 20 is de-energized, i.e., no excitation current is supplied thereto, minimizing the normal force to facilitate removal of the copy sheet from transport 10.