Electrostatic copying machine having flash-discharge-lamp fixing unit

An improved electrostatic copying machine of the type provided with a fixing station comprising a reflector and means including a flash lamp located within the reflector for fusing a toner image on a copying medium by applying thereto at least one brief high-energy flash of radiant energy to raise the temperature of the toner to its melting point, the improvement comprising means defining a cooling-air passage in the machine, the cooling-air passage including the space surrounding the reflector and flash lamp;

• and filter means provided in the cooling-air passage downstream of the reflector and flash lamp for removing from cooling air flowing through the cooling-air passage contaminants picked up in the vicinity of the reflector and flash lamp, said cooling-air passage being a first cooling-air passage, furthermore comprising means defining a second cooling-air passage extending through a different part of the interior of the copying machine, means establishing the flow of a first stream of cooling air through the first cooling-air passage and filter means and the flow of a second stream of cooling air through the second cooling-air passage of greater volumetric flow rate than the first stream of cooling air, and means at the downstream ends of the first and second cooling-air passages for effecting the discharge of cooling air from the cooling-air passage to the exterior of the copying machine and preliminary to such discharge the mixing together of the first and second streams of cooling air, to thereby dilute the first stream of cooling air by mixing the latter into the higher-volumetric-flow-rate second stream of cooling air prior to discharge.