Sheet feeder and copying machine including the same

Abstract

A sheet feeder includes: a sheet-length detection member for detecting a length of a sheet; a transfer-length detection member for detecting a transfer length of the sheet; a double-feed detection member for detecting double feed of the sheets when the sheets are transferred while being overlapped with one another; and a control member for controlling the sheet-length detection member, the transfer-length detection member and the double-feed detection member; wherein the control member determines that double feed of the sheets has occurred, when the transfer length of the sheet is greater than the length of the sheet and a length obtained by subtracting a difference between the transfer length of the sheet and the length of the sheet from the length of the sheet is substantially equal to a double-feed length detected by the double-feed detection member.

Dependencies are inferred from the claim text.