Patent ID: 7887039

Claim:
An image forming apparatus comprising: a main body; a return path to divert a paper printed on one surface back to the main body so that the paper printed on one surface can be printed on a second surface; and a paper feeding unit removably mounted to the main body and having a paper container with a knock-up plate to lift a front end of paper within the paper container, a paper supply case to manually supply paper to the main body, a paper aligning unit mounted above the knock-up plate to an upper side of the paper container to align a picked-up paper from the paper container and supply the picked-up paper to the main body, the paper aligning unit having a shutter to abut the picked-up paper traveling from the paper container, and a reverse feed tray to guide the paper along the return path, wherein the paper supply case comprises a manually paper feeding path to feed paper to the paper aligning unit, a pickup roller to pick up paper loaded on the paper supply case and feed rollers disposed on the manually paper feeding path between the pickup roller and the shutter, wherein the paper container, the shutter, the reverse feed tray and the feed rollers constitute a unitary unit, and the paper aligning unit, the reverse feed tray, and the feed rollers are mounted to or separated from the main body along with the paper container when the paper feeding unit is mounted to or separated from the main body.