A medium transport device includes a feed roller, a separation roller that nips the medium P together with the feed roller and separates a plurality of stacked medium, a drive section that generates a driving force, a one way clutch section provided in a transmission path for transmitting the driving force to the feed roller, wherein the one way clutch section is configured to switch between an allowed state in which the feed roller allowed to rotate in a rotation direction in which the medium are moved in a reverse feed direction and a restricted state in which this is not allowed and it is causes the one way clutch section to the allowed state, and that is configured to rotate the separation roller in the rotation direction in which the medium moves in the reverse feed direction.

A sheet feeder includes: a multi-purpose tray; a guide roller provided at an end of the multi-purpose tray to come into contact a recording paper sheet protruding from the end of the multi-purpose tray; a spring member that supports the guide roller elastically and movably in upward and downward directions; and a pick-up roller that is disposed apart from the end of the multi-purpose tray movably in the upward and downward directions and, when moved downward, pulls out the recording paper sheet protruding across an upper side of a peripheral surface of the guide roller from the end of the multi-purpose tray while being pressed against a leading end portion of the recording paper sheet.

A feeding roller feeds a medium placed at a medium placement portion by forward rotation power supplied from a driving unit. A displacement portion displaces the feeding roller to an abutting position by the forward rotation power supplied from the driving unit and displaces the feeding roller to a separation position by reverse rotation power supplied from the driving unit. A power transmission unit includes a one-way clutch that transmits the forward rotation power, that is supplied from the driving unit, to the feeding roller but does not transmit the reverse rotation power, that is supplied from the driving unit, to the feeding roller.

Provided is a sheet feeding device including: a cassette housing section; a sheet storage cassette; and a sheet feeding unit. The sheet storage cassette includes a cassette base which is configured to store recording media that have a sheet form, and can be inserted into and removed from the cassette housing section. The sheet feeding unit is provided in the cassette housing section, and is configured to feed the recording media to be stored in the sheet storage cassette. A pair of fixed-side rails that are made of metal and are attached to the cassette housing section. The cassette base is made of a resin. A pair of inner rails that are coupled to the pair of fixed-side rails so that the pair of inner rails are slidable are formed integrally with side surfaces of the cassette base.

A sheet feeding device includes a pick-up roller, a sensor, and a sheet feeding controller. The pick-up roller draws out a plurality of sheets one by one from a sheet table on which the plurality of sheets are loaded. The sensor detects presence or absence of the sheet. The sheet feeding controller controls drive to raise the pick-up roller on the basis of a detection result of the sensor.