Sheet transfer apparatus and image reading apparatus

A sheet transfer apparatus for an image reading apparatus having a platen and a frame to read an image on a sheet, comprising:

• a sheet supply tray for storing the sheet;
• sheet supply means disposed adjacent to the sheet supply tray for drawing out the sheet on the sheet supply tray;
• transfer means disposed adjacent to the sheet supply means for receiving the sheet from the sheet supply means and placing the sheet at a predetermined position on the platen of the image reading apparatus for reading the image thereon;
• discharge means disposed adjacent to the platen for discharging the sheet on the platen after reading the image thereon;
• a discharge tray located above the sheet supply tray and arranged adjacent to the discharge means for receiving the sheet discharged by the discharge means;
• and
• switchback means disposed above the platen for reversing the sheet when necessary, and including a switchback path having an inlet side for receiving the sheet to reverse the same, a first opening portion for opening a first area near the inlet side, and a second opening portion for opening a second area away from the inlet side of the switchback path, said switchback path being located below the sheet supply tray separately from a space above the sheet supply tray.