Sheet Feeder Capable of Reliably Conveying Sheet

A sheet feeder comprising:

• a casing including:
• a first casing having a first surface;
• and
• a second casing connected to the first casing and movable relative to the first casing between an open position and a closed position, the second casing having a second surface, the second surface facing the first surface with a gap between the first surface and the second surface when the second casing is at the closed position,
• the casing defining a conveying path between the first surface and the second surface when the second casing is at the closed position;
• a first roller having a portion protruding from the first surface, the first roller being configured to convey a medium in a conveying direction along the conveying path;
• a pressing portion movable between a first position and a second position via a third position when the second casing is at the closed position, the pressing portion in the first position facing the first roller, the pressing portion in the second position being separated from the first roller farther than in the first position, the third position being located between the first position and the second position;
• a first spring configured to urge the pressing portion toward the first roller when the pressing portion is disposed between the first position and the second position;
• a second spring configured to urge the pressing portion toward the first roller when the pressing portion is disposed between the second position and the third position;
• and
• a cam portion being configured to rotate in one direction and in another direction, the cam portion contacting the pressing portion to move the pressing portion from the first position to the second position when the cam portion rotates in the one direction, the cam portion separating from the pressing portion to allow the pressing portion to move from the second position to the first position when the cam portion rotates in the other direction.

A sheet feeder comprising:

• a first roller configured to convey a medium in a conveying direction;
• a separation member having an upstream end in the conveying direction;
• a pressing portion movable between a first position and a second position via a third position, the pressing portion in the first position facing the first roller, the pressing portion in the second position separated from the first roller farther than in the first position, the third position being located between the first position and the second position, the pressing portion having a nearest end portion positioned nearest the first roller, the nearest end portion of the pressing portion being positioned upstream of the upstream end of the separation member in the conveying direction when the pressing portion is in the first position;
• a first spring configured to urge the pressing portion toward the first roller when the pressing portion is disposed between the first position and the second position;
• and
• a second spring configured to urge the pressing portion toward the first roller when the pressing portion is disposed between the second position and the third position.