In an image formation state, to cool a recording sheet on a route from a fixer to a paper ejection roller, a blast fan assumes a first position restrained by a first fixture. Also, in another state, to cool a recording sheet on the catch tray, the blast fan assumes a second position restrained by a second fixture. To transition from the image formation state to another state, the blast fan sends a strong blast in a reverse direction from the normal blast direction. A bias is generated on the blast fan due to the resulting reactive force, the blast fan becomes free from the restraint of the first fixture, and shifts from the first position to the second position. Conversely, to transition from another state to the image formation state, a strong blast is sent in the same direction as the normal blast direction, and the blast fan shifts from the second position to the first position.