Sheet feeding device and image forming apparatus

A sheet feeding device comprising:

• a driving transmission member configured to rotate around a first rotation axis;
• a storage unit including a stacking member and configured to store sheets stacked on the stacking member;
• a feeding unit configured to be detachable from the sheet feeding device and including a driven transmission member, a feeding member, and a holding member configured to hold the driven transmission member and the feeding member, wherein the driven transmission member is configured to be engageable with the driving transmission member and to receive a driving force from the driving transmission member in a state where the feeding unit is attached to the sheet feeding device, and the feeding member is configured to rotate by rotation of the driven transmission member being rotated by the received driving force and to feed the sheets stacked on the stacking member;
• a separation unit configured to separate the sheets fed by the feeding unit one by one;
• and
• a switching member configured to abut on the holding member and to switch a position of the feeding member by moving the feeding member between a second position and a first position lowered from the second position,
• wherein, in a state where the driving force is transmitted from the driving transmission member to the driven transmission member, the feeding unit is positioned to the sheet feeding device by receiving a positioning force in an attachment direction of the feeding unit, and
• wherein, in a state where the driving force is not transmitted from the driving transmission member to the driven transmission member, the feeding unit is regulated by the switching member in movement in a direction that is opposite to the attachment direction of the feeding unit, and
• wherein the switching member includes a pressing portion configured to press the holding member to move the feeding member from the second position to the first position, and includes a regulation portion configured to regulate movement of the feeding unit in the opposite direction.