Patent ID: 8690152
Filing Date: 2014-04-08
Classification: B65H

Abstract:
1. A sheet conveyor comprising: a first roller pair including a roller to which a torque limit of a torque limiter is imparted; a second roller pair disposed downstream of the first roller pair in a sheet conveyance direction; a drive shaft; motors that drive the drive shaft and the second roller pair; first and second electromagnetic clutches configured to be selectively engaged to couple the drive shaft to the first roller pair and selectively transmit torque to rotate the first roller pair; a processor causing, in a first drive mode, the first roller pair to be coupled to the drive shaft through a first transmission mechanism using the first electromagnetic clutch so as to rotate at a higher peripheral velocity than a peripheral velocity of the second roller pair, in a second drive mode, the second roller pair is kept rotating whereas the first roller pair is not driven, and in a third drive mode, the first roller pair is coupled to the drive shaft through a second transmission mechanism using the second electromagnetic clutch so as to rotate at a lower peripheral velocity than a peripheral velocity of the second roller pair; the processor providing a first control to select the first drive mode to allow the sheet to form a loop between the first roller pair and the second roller pair, a second control to select the second drive mode to decrease the loop, and a third control to select the third drive mode after the loop reaches a predetermined amount, to lower a velocity of clearing the loop from a velocity of clearing the loop of the second control; and wherein the processor repeats an operation of selecting the third control for a fixed period of time followed by selecting the second control until the loop clearance is confirmed.