Sheet stacker

A paper sheet accumulator assembly for receiving paper sheets to accumulate the same to be ready for collective dispensation. The paper sheet accumulator assembly includes a plurality of paddle wheels each having a plurality of paddles overlapping each other. Paper sheets fed by a conveyer between the paddles as the paddle wheels rotate. A guide belt assembly is provided adjacent to the paddle wheels to restrain the free movement of the trailing ends of the paper sheets and to prevent the paper sheets from slipping out the paddle wheels. The guide belt assembly is driven to move at a speed substantially equal to the circumferential speed of the trailing free ends of the paddles so as to facilitate smooth travel of the paper sheets carried by the paddle wheels. The paper sheet accumulator assembly further includes a scraper plate disposed below the paddle wheels for scraping the paper sheets away from the paddle wheels, and a carrier plate for receiving the paper sheets scraped from the paddle wheels.