An image forming apparatus includes first and second image bearing drums; first and second developing devices; an intermediary transfer member; a cleaning device for collecting toner remaining on the intermediary transfer member; a heater for heating a recording material; an executing portion capable of executing an operation in a first mode for forming an image on the intermediary transfer member from the first and second image bearing drums and an operation in a second mode for forming an image on the intermediary transfer member only from the second drum; a temperature detecting portion disposed in the apparatus; a fan for feeding air in the apparatus; a controller for controlling the fan based on an output of the temperature detecting portion; and a setting portion for setting a temperature, wherein the temperature at which an air feed amount is increased in the second mode is lower than in the first mode.