Medium feeding apparatus and image reading apparatus

A medium feeding apparatus comprising:

• a medium placing unit on which a medium is placed;
• a feeding roller that feeds the medium from the medium placing unit;
• a separation roller which nips the medium between the separation roller and the feeding roller to separate the medium and to which a driving torque is applied by a driving source in a second rotation direction that is opposite to a first rotation direction in which the medium is fed to a downstream side;
• a torque limiter that causes the separation roller to idle in the first rotation direction when a rotational torque applied to the separation roller in the first rotation direction exceeds a limit torque that is a predetermined upper torque limit;
• a load changing unit that changes a pressing load of the separation roller against the feeding roller;
• a speed changing unit that changes a rotational speed of the driving source;
• and
• a torque changing unit that changes the limit torque,
• wherein separation setting including the pressing load, the rotational speed, and the limit torque is changeable according to condition of feeding.

A medium feeding apparatus comprising:

• a medium placing unit on which a medium is placed;
• a feeding roller that feeds the medium from the medium placing unit;
• a separation roller which nips the medium between the separation roller and the feeding roller to separate the medium and to which a driving torque is applied by a driving source in a second rotation direction that is opposite to a first rotation direction in which the medium is fed to a downstream side;
• a torque limiter that causes the separation roller to idle in the first rotation direction when a rotational torque applied to the separation roller in the first rotation direction exceeds a limit torque that is a predetermined upper torque limit;
• a torque changing unit that changes the limit torque;
• and
• a speed changing unit that changes a rotational speed of the driving source,
• wherein separation setting including the rotational speed and the limit torque is changeable according to condition of feeding.