1. Field of the Invention
The present invention relates to a document feeder provided to an image reader having a reading device that reads an image, at a reading position, from a document that is being conveyed. The present invention particularly relates to a thin document feeder having a substantially U-shaped document transporting pathway for conveying the document from a sheet feeding portion to a sheet discharging portion through the reading position.
2. Description of the Related Art
There is an imaging reader that is capable of reading an image recording surface of a stationary document and a moving document. Such the image reader is generally provided with two kinds of transparent plates (glass plates) for reading a stationary document and a moving document, on a body of the image reader. To read a stationary document, a document is placed on one of the transparent plates (flatbed type) and is pressed by a cover capable of opening and closing with respect to the body of the image reader. The document is then read by an image scanner (an image reading device) moving along an underside of the transparent plate (flatbed type). In the case of reading a moving document, a plurality of documents stacking on a feeding tray is separated one by one by an automatic document feeder (ADF) disposed on the cover, and is conveyed to the transparent plate. After the image recording surface is read by the image reading device halting under the transparent plate, the document is discharged to a discharging tray.
The document transporting pathway may be generally provided in automatic document feeders. One type of the ADFs may be an upper feeding type, for example, disclosed in Japanese Patent Laid-Open Patent Publication No. 2003-76074 (FIG. 1). This type of the ADF has a substantially U-shaped document transporting pathway that extends from a sheet feeding portion located at the upper side to a discharging portion located at the lower side, through a document reading position. Another type of the ADFs may be a lower feeding type, for example, disclosed in Japanese Laid-Open Patent Publication No. 2002-335372 (FIG. 1). This type of the ADF has a substantially U-shaped document transporting pathway that extents from a sheet feeding portion located at the lower side to a discharging portion located at the upper side, through a document reading position.
In the ADF disclosed in JP2003-76074, a pickup roller, a separating roller and first and second pairs of transporting rollers are disposed at positions upstream from the document reading position (the upper side of the body of the ADF) with respect to the document conveying direction in the substantially U-shaped document transporting pathway. A pair of discharging rollers is disposed at a position downstream from the document reading position with respect to the document conveying direction. A document stacking tray is tilted downward facing the pickup rollers and is disposed at a position upstream from the pickup roller with respect to the document conveying direction. A document discharging tray is arranged under the document stacking tray. In the ADF disclosed in JP2002-335372, a document feeding tray is disposed above and in parallel with a transparent plate for a stationary document. A pickup roller and a separating pad are disposed at a position downstream from the document feeding tray with respect to the document conveying direction. A pair of transporting rollers is disposed at a position downstream from the separating pad with respect to the document conveying direction. Contact rollers are disposed at the front and back of a reading position where a document that is being conveyed is read, in the document conveying direction. A substantially sideways U-shaped transporting pathway is provided at a position downstream from the contact rollers in order to turn a document so that a recording surface of the document faces up. A pair of discharging rollers is provided at a downstream position of the substantially U-shaped transporting pathway (at a discharging side) with respect to the document conveying direction.