Document feeder

A document feeder comprising:

• a conveying path which is extended from a document supplying position in a predetermined direction, curved downward so as to reverse a sheet feed direction and reaching a reading position, the conveying path guiding a document from the reading position to a reverse sheet feed direction which is opposed to the sheet feed direction;
• a first conveying roller pair which is provided upstream in the sheet feed direction from the reading position of the conveying path and is provided above the reading position, the first conveying roller pair nipping and conveying the document passing through the conveying path;
• a second conveying roller pair which is provided downstream in the sheet feed direction from the reading position of the conveying path and is provided above the reading position, the second conveying roller pair nipping and conveying the document passing through the conveying path at a document conveying speed faster than the first conveying roller pair;
• a post-reading conveying path which is provided in the conveying path and is extended from a nipping position of the second conveying roller pair in a downstream direction, the post-reading conveying path being located above a plane tangent to the second conveying roller pair at the nipping position running in the reverse sheet feed direction;
• and
• a third conveying roller pair which is provided on the post-reading conveying path, the third conveying roller pair nipping and conveying the document conveyed from the second conveying roller pair at a conveying force equivalent to that of the second conveying roller pair,
• wherein an intersection portion of the conveying path with the post-reading conveying path is located in the reverse sheet feed direction from the nipping position of the second conveying roller pair, and
• wherein the third conveying roller pair holds the document at a nipping pressure lower than that of the second conveying roller pair.

A document feeder comprising:

• a conveying path which is extended from a document supplying position in a predetermined direction, curved downward so as to reverse a sheet feed direction and reaching a reading position, the conveying path guiding a document from the reading position to a reverse sheet feed direction which is opposed to the sheet feed direction;
• a first conveying roller pair which is provided upstream in the sheet feed direction from the reading position of the conveying path and is provided above the reading position, the first conveying roller pair nipping and conveying the document passing through the conveying path;
• a second conveying roller pair which is provided downstream in the sheet feed direction from the reading position of the conveying path and is provided above the reading position, the second conveying roller pair nipping and conveying the document passing through the conveying path at a document conveying speed faster than the first conveying roller pair;
• a post-reading conveying path which is provided in the conveying path and is extended from a nipping position of the second conveying roller pair in a downstream direction having a slope relative to a horizontal plane, the slope being as large as a slope of a line which is tangent to the second conveying roller pair at the nipping position running in the reverse sheet feed direction relative to the horizontal plane;
• and
• a third conveying roller pair which is provided on the post-reading conveying path, the third conveying roller pair nipping and conveying the document conveyed from the second conveying roller pair at a conveying force equivalent to that of the second conveying roller pair,
• wherein an intersection portion of the conveying path with the post-reading conveying path is located in the reverse sheet feed direction from the nipping position of the second conveying roller pair, and
• wherein the post-reading conveying path is extended above the document supplying position.