Patent ID: 7237857

Claim:
An image forming apparatus comprising: a carrier having a print head; wherein the carrier is reciprocatingly set in a body of the image forming apparatus; a driving motor to provide a rotational driving force to at least one roller set in the body of the image forming apparatus to transfer a print paper; and a disc-printing unit, in which a disc is rotatably seated within a moving area of the carrier wherein the disc-printing unit rotates the disc by a driving force of the driving motor during a printing operation, wherein the disc-printing unit comprises a revolvable platform having a vertical axis and positioned under the carrier at a lateral end area of the at least one roller, in which the disc is seated on the revolvable platform; and a power transfer unit to transmit the rotational force of the at least one roller to the revolvable platform, wherein the power transfer unit comprises a driven gear connected downwardly along the vertical axis of the revolvable platform; a driving gear connected to a rotational shaft of the at least one roller; and a clutch unit located between the driving gear and the driven gear to intermittently transmit the rotational force of the driving gear to the driven gear, wherein the driven gear is a worm wheel and the driving gear is provided with a plurality of first projections projected along the axial direction of the feeding roller, and wherein the clutch unit comprises an intermediate gear comprising of a worm part located parallel to the rotational shaft of the at least one roller and engaged with the worm wheel, and a gear part extended in the radial direction from an end of the worm part; a clutch gear provided with a plurality of second projections to be engaged with the first projections of the driving gear, in which the clutch gear is movable along the axis of the feeding roller when engaged with the gear part of the intermediate gear; and a solenoid device to move the clutch gear between an engagement position, where the clutch gear is engaged with the driving gear, and a disengagement position, where the clutch gear is released from the engagement with the driving gear.