Medium feeding device, recording device, feeding roller unit, and method of controlling recording device

A medium feeding device comprising:

• a feeding roller configured to feed a medium placed at a medium placement portion;
• a driving unit configured to drive the feeding roller;
• a displacement portion configured to displace the feeding roller between an abutting position and a separation position;
• and
• a power transmission unit configured to transmit power, that is supplied from the driving unit, to the feeding roller and the displacement portion,
• wherein
• the abutting position is a position at which the feeding roller abuts on the medium placed at the medium placement portion,
• the separation position is a position at which the feeding roller is separated from the medium placed at the medium placement portion,
• the feeding roller feeds the medium placed at the medium placement portion by forward rotation power supplied from the driving unit, and
• the displacement portion displaces the feeding roller to the abutting position by the forward rotation power supplied from the driving unit and displaces the feeding roller to the separation position by reverse rotation power supplied from the driving unit, and the power transmission unit includes a one-way clutch that transmits the forward rotation power supplied from the driving unit to the feeding roller but does not transmit the reverse rotation power supplied from the driving unit to the feeding roller.