Sheet feeding apparatus, image forming apparatus, and extension supporting unit

A sheet feeding apparatus comprising:

• a first sheet supporting unit including a first sheet supporting surface configured to support a sheet;
• a feeding portion configured to feed the sheet supported on the first sheet supporting surface in a sheet feeding direction;
• and
• a second sheet supporting unit detachably attached to the first sheet supporting unit, and positioned upstream of the first sheet supporting surface in the sheet feeding direction to support a sheet in an attached state where the second sheet supporting unit is attached to the first sheet supporting unit,
• wherein, in the attached state, the second sheet supporting unit includes
• a first supporting portion including a second sheet supporting surface extending upstream in the sheet feeding direction from the first sheet supporting surface,
• a second supporting portion including a third sheet supporting surface disposed upstream of the second sheet supporting surface in the sheet feeding direction and configured to support a long sheet together with the first sheet supporting surface and the second sheet supporting surface, and
• a bending portion connecting the second supporting portion continuously to the first supporting portion in an upwardly bent state, and
• wherein, in a state where a regular size sheet is supported on the first sheet supporting surface and the second sheet supporting surface, the first supporting portion has a length extending upstream of an upstream edge portion of the regular size sheet in the sheet feeding direction.