Patent ID: 7764920

Claim:
A duplex document feeder adapted for an image forming apparatus, the image forming apparatus including a scanning unit, said duplex document feeder comprising: a housing unit having a document-conveying path, an inverting path in spatial communication with an intermediate portion of said document-conveying path, and a switchback path located at one side of an assembly of said document-conveying path and said inverting path, said document-conveying path having a document-feeding end and a document-discharging end, said inverting path having an inlet end aligned with said document-discharging end, and an outlet end in spatial communication with said document-conveying path, said switchback path being in spatial communication with said document-discharging end and said inlet end, the scanning unit being disposed between said outlet end and said document-discharging end; and a switching unit disposed pivotally in said switchback path and including a first switching gate, a second switching gate connected fixedly to and disposed under said first switching gate, and a guiding path disposed between said first and second switching gates, said switching unit being pivotable in said switchback path among a first position whereat a free end of said first switching gate is disposed under said document-discharging end such that a top portion of said first switching gate is in spatial communication with both said document-discharging end and said inlet end, a second position whereat said free end of said first switching gate is disposed in proximity to said inlet end such that said inlet end is in spatial communication with said top portion of said first switching gate and whereat said document-discharging end is in spatial communication with said guiding path, and a third position whereat said guiding path is aligned with said inlet end such that said inlet end is in spatial communication with said guiding path and whereat said document-discharging end is in spatial communication with a bottom portion of said second switching gate.