Patent ID: 7931265

Claim:
A sheet feeder, comprising: a feed roller configured to contact and feed a top sheet of a stack of sheets while rotating in a predetermined feeding direction; an input gear mechanism for transmitting a driving force; a driving gear configured to be rotated in a predetermined direction and transmit the driving force received from the input gear mechanism, the driving gear including a tooth lacking portion, wherein the input gear mechanism does not transmit the driving force to the driving gear when the driving gear is in a home position in which the tooth lacking portion faces the input gear mechanism, and a locking projection; a first gear mechanism configured to transmit the driving force from the driving gear to the feed roller so as to rotate the feed roller in a reverse direction opposite to the feeding direction; a second gear mechanism configured to transmit the driving force from the driving gear to the feed roller so as to rotate the feed roller in the feeding direction; and a locking member configured to engage with the locking projection through rotation of the driving gear, and lock rotation of the driving gear in the home position, wherein the driving gear further includes: a first engaging member configured to engage with the first gear mechanism and transmit the driving force to the first gear mechanism when a rotational angle of the driving gear is within a first range; and a second engaging member configured to engage with the second gear mechanism and transmit the driving force to the second gear mechanism when the rotational angle of the driving gear is within a second range that has no common range with the first range.