AIR CLEANER AND REPLACEMENT ALARM METHOD OF DUST FILTER OF THE SAME

PURPOSE: An air purifier and a method for informing the filter exchanging timing of the air purifier are provided to maintain the air purifying capability of the air purifier by confirming the dust collecting state of a filter and changing the number of rotation of a motor. CONSTITUTION: An air purifier includes a filter(140), a blowing fan(132), a motor(150), a blowing amount measuring part(160), and a controlling part(180). The filter purifies air sucked in a body part. The blowing fan discharges purified air. The blowing amount measuring part measures the blowing amount of the discharged air. The motor rotates the blowing fan. The controlling part controls the number of rotation of the motor. The controlling part verifies a filter exchanging timing. A displaying part(190) is further included in the air purifier and displays the filtering exchanging timing.