Patent ID: 8065778

Claim:
A robot cleaner comprising: a cleaner body; a dust tank separably engaged with the cleaner body in a horizontal direction to collect dust; and a backward-flow preventing device to prevent dust from flowing backward outside through a suction port provided at a lower portion of a side surface of the dust tank, wherein the backward-flow preventing device includes a shutter unit mounted at the side surface of the dust tank to open and close the suction port and a stopper unit mounted at a side surface of the cleaner body corresponding to the installation place of the shutter unit to drive the shutter unit, wherein the shutter unit includes an opening and closing plate hingedly mounted at the suction port side, a pivotable lever to hingedly rotate the opening and closing plate, and wherein the stopper unit is movable between first and second positions, and the stopper unit pushes the lever, such that the lever is hingedly rotated, to open the opening and closing plate in the first position, and the stopper unit releases the pushed state of the lever to close the opening and closing plate in the second position.