A paper arranging device includes a driving roller and an idle roller disposed adjacent to each other to form a nip, a first sensor to sense a location of moving paper, and a lever having a first end which extends to a perimeter of the nip to block a tip of the paper moving toward the nip and the other end which extends to a perimeter of the sensor, the lever being rotatable with respect to a predetermined pivot axis between the first end and the second end of the lever. When the first end of the lever is pressed by the tip of the moving paper and reaches a first position, the first sensor determines that the tip of the paper is entering the nip and generates a first sensing signal. When the first end of the lever is pressed by the tip of the moving paper and reaches a second position at which the paper has proceeded farther than at the first position, the first sensor determines that the tip of the paper passes through the nip and generates a second sensing signal.