A fixing device is provided in image forming apparatuses such as a printer and the like and performs a fixing by heating to a recording sheet on which a toner image is transferred. According to the invention, the rehumidification stage of the treated dry air comprises an operation of controlled distribution of the treated dry air on the one hand in a rehumidification line, and on the other hand in a dry line. The basis of this invention is a complementary Junction Field Effect Transistor which is operated in the enhancement mode. The first and second decoders are coupled to the pipeline and decode register identifiers associated with instructions being processed by the pipeline. A bubble introducer introduces micro-sized gas bubbles into the fluid mixture so as to thereby enhance the separation of the fluid components. A surrounding space in the relief valve chamber is directly connected to a pumping portion of the oil pump.