Patent ID: 7929869
Filing Date: 2011-04-19
Classification: G03G

Abstract:
1. A sheet feeder, comprising: a transporter, adapted to transport a sheet in a transport direction along a transport path that includes a detecting range, the detecting range including a first range and a second range disposed at a downstream side of the first range in the transport direction, the transporter including a picking section from which the sheet is transported in the transport path and that is disposed at an upstream end of the first range in the transport direction and a separating section through which the sheet passes one by one and that is disposed at an upstream end of the second range in the transport direction; a first measurer, disposed at the picking section, and operable to measure a moving distance of the sheet while the sheet is transported by the transporter, the first measurer including a first driven roller configured to freely rotate around a common drive shaft with the picking section and to be driven by the sheet when the sheet passes the picking section; a second measurer, disposed at the separating section, and operable to measure a moving distance of the sheet while the sheet is transported by the transporter and to detect a leading end edge of the sheet, the second measurer including a second driven roller configured to freely rotate around a common drive shaft with the separating section and to be driven by the sheet when the sheet passes the separating section; a detector, disposed at a downstream end of the second range in the transport direction, and operable to detect the leading end edge of the sheet; and a processor, operable to detect a jam either when the moving distance of the sheet measured by the first measurer becomes longer than a length of the first range in the transport direction and the leading end edge of the sheet is not detected by the second measurer, or when the moving distance measured by the second measurer becomes longer than a length of the second range in the transport direction and the leading end edge of the sheet is not detected by the detector.