Patent ID: 8172217
Filing Date: 2012-05-08
Classification: B65H

Abstract:
1. A sheet material transport apparatus comprising: a first transport roller and a second transport roller that transport a sheet material; and a gear train mechanism that, when the first transport roller rotates in the forward rotation direction or the backward rotation direction due to the driving force of a rotational means, transmits the rotational driving force of the first transport roller to the second transport roller and causes the second transport roller to undergo slave rotation in the forward rotation direction, wherein the gear train mechanism includes: a transmission gear that transmits the rotational driving force to the second transport roller; a sun gear provided so as to engage the first transport roller and that rotates in one of a forward direction and a backward direction based on the rotational driving of the first transport roller; a first planetary gear, provided so as to engage with the sun gear and to be capable of planetary motion around the sun gear, that is positioned in a first engaging position capable of engaging with the transmission gear when the sun gear undergoes forward-direction rotation and is positioned in a first separated position not capable of engaging with the transmission gear when the sun gear undergoes reverse-direction rotation; and a second planetary gear, provided so as to engage with the transmission gear and to be capable of planetary motion around the transmission gear, the second planetary gear provided so as to engage the first planetary gear in a second engaging position, the second planetary gear being capable of being positioned in a second separated position where the second planetary gear is not engaged with the first planetary gear during forward-direction rotation, wherein while the second planetary gear is in the second separated position the transmission gear engages with the first planetary gear and the transmission gear rotates in the direction that causes the second transport roller to rotate in the forward rotation direction, and the second planetary gear capable of being positioned in a second engaging position where the second planetary gear is engaged with the first planetary gear, wherein while the second planetary gear is in the second engaging position the first planetary gear is positioned in the first engaging position during reverse-direction rotation, a load is placed on the transmission gear by the second transport roller and the transmission gear rotates in the opposite direction to the forward-direction rotation, the second planetary gear applying a force on the first planetary gear in the direction that separates the first planetary gear from the transmission gear due to rotation in the second engaging position.