Patent ID: 7918451

Claim:
A switchback mechanism, comprising: a first roller group composed of a first roller, a second roller, and a third roller, the second roller being in contact with the first roller and the third roller; a second roller group composed of a fourth roller and a fifth roller, the fourth roller and the fifth roller being in contact with each other; a switching guide that rotates around a rotating shaft supported by a supporting member, and switches a conveying path of a sheet between a switchback conveying path and a non-switchback conveying path, the switchback conveying path connecting between a first nip portion formed between the fourth roller and the fifth roller and a second nip portion formed between the second roller and the third roller, and the non-switchback conveying path connecting between the second nip portion and a third nip portion formed between the first roller and the second roller via the first nip portion; a drive gear that is coupled to the fourth roller, and rotates in a first direction by receiving a drive force from the fourth roller; a first transmission-gear group that is composed of even numbers of transmission gears, and transmits a drive force from the drive gear to the transmission gears as a rotation in the first direction; a second transmission-gear group that is composed of odd numbers of transmission gears, and transmits the drive force from the drive gear to the transmission gears as a rotation in a second direction opposite to the first direction; a switching gear that is connected to one of the first transmission-gear group and the second transmission-gear group, and transmits the drive force from the drive gear to the second roller as one of the rotation in the first direction and the rotation in the second direction via a third transmission-gear group composed of even numbers of transmission gears; a first link that the switching gear is attached to one end thereof, and rotates around the rotating shaft to switch a connection of the switching gear to one of the first transmission-gear group and the second transmission-gear group; and a second link that is connected to the other end of the first link to interlock the connection of the switching gear to one of the first transmission-gear group and the second transmission-gear group with a conveyance of the sheet to one of the switchback conveying path and the non-switchback conveying path switched by the switching guide.