A first rotary image carrier is adapted to support a toner image obtained by developing an electrostatic latent image formed thereon. A second rotary image carrier is adapted to support, on a toner supporting face thereof, the toner image which has been primarily transferred from the first rotary image carrier and is to be secondarily transferred onto a recording medium. A cleaner housing has wall members defining a housing space, a first one of which is formed with a first ventilation hole. A blade member is disposed in the housing space and configured to separatably come in contact with the second rotary image carrier to scrape off toner remaining thereon. A sealing member is disposed in the housing space and configured to separatably come in contact with the second rotary image carrier to form a closed space together with the blade member. An air duct, a part of which is formed by an outer face of at least one of the wall members of the cleaner housing, communicates with the housing space through the first ventilation hole.