Patent ID: 8478182

Claim:
An image forming apparatus comprising: a printing medium supply unit to supply a printing medium to a feeding path; a printing unit to print an image on the printing medium; and a printing medium alignment device comprising, a register roller, an idle roller to form a nip with the register roller, to feed the printing medium along the feeding path to the printing unit, wherein the idle roller rotates on a fixed support shaft, a register shutter to move to a first position to block the printing medium from entering the nip and align the printing medium, and to move to a second position to allow the printing medium to enter the nip, wherein the register shutter is loosely coupled to said fixed support shaft; and at least one shutter roller mounted on the register shutter, to rotate to decrease friction between the printing medium and the register shutter, when the register shutter is in the second position, wherein the register shutter comprises a front-end touch part having a front-end touch surface to contact the front-end of the printing medium and block the printing medium from entering the nip and align the printing medium, and the shutter roller is mounted on the front-end touch part, and wherein the shutter roller is mounted such that an outer peripheral surface of the shutter roller, which contacts the printing medium when the register shutter is in the second position, protrudes from the front-end touch surface.