Patent ID: 7455284

Claim:
A paper alignment device. that aligns first size paper and second size paper being larger than the first size paper into a bundle of paper fed from an upstream device, comprising: a size sensor detecting paper size of paper fed from the upstream device; a main retaining device having a paper receiving unit contactable to an end of the paper being fed and retaining in a stacked condition the bundle of paper; a preliminary retaining device located in a paper transfer direction upstream of the main retaining device, the preliminary retaining device temporarily retaining only first size paper destined to the main retaining device; and a control unit causing the first size paper in the preliminary retaining device to be retained when fed under a predetermined condition, and causing feeding to the main retaining device of the first size paper retained in the preliminary retaining device together with successively fed second size paper, the predetermined condition being realized when a first size paper is fed subsequent to a first fed sheet of paper being a second size paper.