Paper sheet stacking mechanism and paper sheet handling device

A paper sheet stacking mechanism comprising:

• a stacking unit configured to stack paper sheets therein;
• a pair of stacking wheels provided to be rotatable about a rotary shaft, each stacking wheel having vanes extending outward in a direction opposite to a rotation direction of the stacking wheel, the pair of stacking wheels being configured to transport a paper sheet inserted between the vanes to the stacking unit;
• two rotary rollers rotatably provided outside and adjacent to the pair of stacking wheels, the rotary rollers being configured to transport the paper sheet to the stacking unit in cooperation with the stacking wheels;
• transport units provided to be opposed to the two rotary rollers, respectively, the transport units being configured to transport the paper sheet nipped between the transport units and the rotary rollers, at a speed higher than a rotation speed of the stacking wheels, thereby to insert the paper sheet between the vanes of the stacking wheels;
• and
• a guide provided between the pair of stacking wheels, the guide having a guide surface configured to guide the paper sheet by coming into contact with a face of the paper sheet that is inserted between the vanes of the stacking wheels by the transport units and transported in accordance with rotation of the stacking wheels, wherein
• the guide surface has a curved shape having a diameter about the rotary shaft, the diameter gradually increasing from an upstream side toward a downstream side in the rotation direction of the stacking wheels.