Patent ID: 8800986
Filing Date: 2014-08-12
Classification: B65H,G03G

Abstract:
1. An image forming apparatus configured to form an image onto a sheet, comprising: a body; a feeding tray configured to receive stacking of a plurality of sheets thereon; a pickup roller configured to contact with an uppermost sheet of the sheets stacked on the feeding tray, from an upper side; a roller supporting mechanism configured to support the pickup roller to be movable in upward and downward directions; a pressing plate swingably provided to the feeding tray and configured to lift up the sheets at a time of feeding the sheets; a lifting mechanism configured to lift the pressing plate; a drive source provided to the body; a drive gear configured to rotate by a driving force transmitted from the drive source; a one-way clutch mechanism configured to rotate only in one direction, and configured to transmit the driving force to the fitting mechanism; a coupling member configured to move in conjunction with a movement of the pickup roller in the upward and downward directions; and a transmission-state switching mechanism engaged with the coupling member, and configured to allow or inhibit the transmission of the driving force from the drive gear to the one-way clutch mechanism, in accordance with movement of the coupling member, wherein the transmission-state switching mechanism includes: a first partially-toothless gear of which a part of an outer periphery is formed as a gear tooth portion to which the driving force is transmitted from the drive gear, and a portion other than the part of the outer periphery is formed as a partially-toothless portion to which the driving force is not transmitted from the drive gear, a second partially-toothless gear of which a part of an outer periphery is formed as a gear tooth portion which transmits the driving force to the one-way clutch mechanism, and a portion other than the part of the outer periphery is formed as a partially-toothless portion which does not transmit the driving force to the one-way clutch mechanism, an engaging portion configured to rotate in conjunction with the first partially-toothless gear, a locking member configured to be engaged with the engaging portion in conjunction with the movement of the coupling member due to an upward movement of the pickup roller, and configured to be disengaged from the engaging portion in conjunction with the movement of the coupling member due to a downward movement of the pickup roller, and a bias applying mechanism configured to apply a bias in the one direction to the first partially-toothless gear and the second partially-toothless gear at a time when at least the locking member engages with the engaging portion, wherein, in the transmission-state switching mechanism, at the time when the locking member engages with the engaging portion, each partially-toothless portion of the first partially-toothless gear and the second partially-toothless gear faces a mechanism on an upstream side of the first partially-toothless gear, and a mechanism on a downstream side of the second partially-toothless gear, and wherein, under a condition that the locking member is disengaged from the engaging portion, the first partially-toothless gear and the second partially-toothless gear are rotated by the bias applying mechanism, and a gear-tooth portion of the first partially-toothless gear is engaged with the mechanism on the upstream side.