Patent ID: 8472859

Claim:
A paper sheet post-processing apparatus comprising: a paper sheet humidifying device, wherein the paper sheet humidifying device comprises: a humidifying roller to convey a paper sheet and apply water to the paper sheet; a water supply roller to supply water to the humidifying roller; a water supply plate to contain the water for dipping the water supply roller, and to eject excessive water by overflowing; a water feeding section to feed the water to the water supply plate; a drain tank to receive the water ejected from the water supply plate, the drain tank comprising a drain outlet to eject the received water; a water level sensor to output a signal when a water level in the drain tank reaches a prescribed level; and a controller to execute a control to prevent overflowing of the water from the drain tank based on the signal from the water level sensor; and wherein the paper sheet post-processing apparatus further comprises: a first conveyance section to convey the paper sheet to the paper sheet humidifying device; a second conveyance section not to convey the paper sheet to the paper sheet humidifying device; and a switching gate to selectively guide the paper sheet to the first conveyance section or to the second conveyance section, wherein the controller controls the switching gate, based on the signal from the water level sensor, so as to switch a conveyance path of the paper sheet from the first conveyance section to the second conveyance section.