Sheet alignment device with mechanism that moves roller support device up and downward

A sheet alignment device comprising:

• a sheet transport route on which a sheet is transported;
• an alignment member provided along a side edge of the sheet located on the sheet transport route;
• a roller that rotates by being contacted by the sheet being transported along the sheet transport route, and makes the side edge of the sheet abut against the alignment member, by moving the sheet in a direction orthogonal to a sheet transport direction;
• a roller support device supporting the roller, the roller support device including a shaft spaced from the roller, and configured to make the roller contact the sheet or move away therefrom, by being supported so as to reciprocatively pivot about the shaft in an up-down direction;
• a motor that provides a rotative driving force;
• a first one-way clutch that transmits a first rotative driving force for making the roller support device pivot upward with respect to the shaft of the roller support device, when the motor rotates in a predetermined first direction;
• a rotation control device that limits rotation of the shaft, when the roller support device is made to pivot upward;
• a first torque limiter that disconnects the first rotative driving force from the first one-way clutch, when the rotation control device limits the rotation of the shaft;
• a second one-way clutch that rotates with a second rotative driving force, generated by a self-weight of the roller support device when the motor is stopped, and making the roller support device pivot downward;
• and
• a second torque limiter that stops the rotation of the shaft, by being subjected to a rotational torque of the second one-way clutch.