A sheet convey apparatus includes a main feed roller, retard roller, torque limiter, retard roller guide, a pair of bearings, and a spring. The main feed roller rotates in a predetermined direction in contact with one surface of a paper sheet, to give to the sheet a force to convey the sheet in a sheet convey direction. The retard roller is arranged to oppose the main feed roller and gives to the sheet with which the retard roller is in contact a force to convey the sheet in a direction opposite to the sheet convey direction. The torque limiter limits a torque of the retard roller and rotates the retard roller in the sheet convey direction when the torque exceeds a predetermined limit. The retard roller guide includes at least a surface inclined with respect to a plane connecting central axes of the main feed roller and retard roller at an angle in a range of 0.degree. (exclusive) to 90.degree. (inclusive). The inclined surface is located in the vicinity of the central axis of the retard roller. The pair of bearings rotatably support a rotating shaft of the retard roller. The spring urges a bearing of the retard roller against the inclined surface of the retard roller guide to generate a component toward the main feed roller which is perpendicular to a reaction force from the inclined surface.

An automatic document feed apparatus includes a document tray having a document positioning surface extending along a transporting direction. A main roller receives a document from the document tray by rotating in the transporting direction. A return roller is pressed against the first roller and rotates in a direction opposite to the transporting direction with a constant torque. Further, a skew-corrective roller which rotates in the transporting direction is provided to prevent skewing of the document in cooperation with the second roller and the document positioning surface.

The image reading apparatus according to the present invention includes a reading device which reads the images of documents fed into an image reading area, a first document feeding device which feeds first documents into the first image reading area of the reading device, and a document feeding unit which is detachably mounted on the first document feeding device and feeds second documents into the second image reading area of the reading device.

An automatic document feeder is provided with a reading unit disposed above a platen for reading an original. The reading unit includes a platen roller for transporting the original to the reading unit; a guide device arranged between the platen and the platen roller and formed in a curved original reading path; a pressing device for pressing the guide device against the platen roller; and a regulating device for creating a space between a surface of the platen roller and an upper surface of the platen. When the original is transported between the platen roller and the guide device, the original moves the guide device toward the platen.

A stand alone flat bed scanner including a CPU, a removable storage medium, a control system displaying digital image and controls for controlling the mode of operation, degree of resolution, related parameters associated with generating, storing and displaying digital data. Ports for printers, accessories and other peripherals, an internal hard drive, and software adapted to display images directly on a television screen, including battery, and a pivotal handle for portable use in environments not having an external power supply.