PURPOSE: To prevent a temperature in a device from raising excessively, by providing an air feeding fan for feeding the open air for cooling to the upper part of a heating part for executing a heating development processing or executing simultaneously a heating development and a transfer, and an exhaust fan for exhausting the cooling air after cooling more than the feed air quantity of a suction fan.

CONSTITUTION: While a transferred image receiving material is being taken out to a take-out tray 54, exhaust heat by a heater 46 is diffused in a developing and transfer means 28, but this dissipation is emitted to the upper part of the developing and transfer means 28 through a heat insulating material of the periphery of a developing and transfer part. In this state, when cooling air from a suction fan 56 is fed to the upper part of the developing and transfer means 28, this exhaust heat is cooled by the cooling air, and the cooling air which has exchanged heat for the exhaust heat is exhausted to the outside by an exhaust fan 62. By making the exhaust quantity of this exhaust fan 62 larger than the feed air quantity of the suction fan 56, the influence by exhaust heat of the heating part is reduced, and it can be prevented that the temperature other than that of the heating part in the device raises excessively.