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

A feeding roller unit comprising:

• a feeding roller configured to feed a medium placed at a medium placement portion;
• a displacement cam configured to displace the feeding roller between an abutting position and a separation position;
• an arm portion configured to support the feeding roller and the displacement cam;
• and
• a power transmission unit configured to transmit power, that is supplied from a driving unit, to the feeding roller and the displacement cam,
• 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,
• the displacement cam 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, and
• the arm portion is rotatable to change a distance between the feeding roller and the medium placement portion.

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 cam configured to displace the feeding roller between an abutting position and a separation position;
• a power transmission unit configured to transmit power, that is supplied from the driving unit, to the feeding roller and the displacement cam;
• and
• a regulator configured to regulate displacement of the displacement cam, 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,
• the displacement cam 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,
• the displacement cam is displaceable between a first position and a second position,
• the first position is a position at which the feeding roller is displaced to the abutting position,
• the second position is a position at which the feeding roller is displaced to the separation position,
• the regulator regulates displacement of the displacement cam at the second position when the displacement cam is displaced from the first position to the second position, and regulates displacement of the displacement cam at the first position when the displacement cam is displaced from the second position to the first position,
• the power transmission unit includes a first power transmission unit that transmits power, that is supplied from the driving unit, to the feeding roller and a second power transmission unit that transmits power, that is supplied from the driving unit, to the displacement cam,
• the first power transmission unit includes the one-way clutch,
• the second power transmission unit includes a torque limiter that interrupts transmission of power by a predetermined load, and
• the torque limiter interrupts transmission of power to the displacement cam when displacement of the displacement cam is regulated by the regulator at the second position, and interrupts transmission of power to the displacement cam when displacement of the displacement cam is regulated by the regulator at the first position.