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

A sheet feeding apparatus comprising:

• a sheet support unit including a sheet supporting surface configured to support a sheet;
• a feed unit configured to feed the sheet supported on the sheet supporting surface;
• and
• an extension support unit configured to be detachably attached to the sheet support unit in a first direction, the extension support unit including an extension supporting surface that is positioned upstream of the sheet supporting surface in a sheet feeding direction and is configured to support the sheet in an attached state in which the extension support unit is attached to the sheet support unit,
• wherein the sheet support unit includes an insertion portion that includes an engagement portion and a contact portion,
• wherein the extension support unit includes an inserted portion, and
• wherein the inserted portion includes:
• an opening portion that is larger than the insertion portion when viewed in the first direction and into which the insertion portion is inserted in the attached state;
• an engaged portion configured to engage and disengage with respect to the engagement portion in a second direction intersecting with the first direction and configured to position the extension support unit with respect to the sheet support unit in the first direction by engaging with the engagement portion in the attached state;
• a contacted portion configured to come into contact with the contact portion in a third direction intersecting with the first direction and the second direction;
• and
• an urging portion configured to urge the contact portion toward the contacted portion in the third direction.