A system for regulating temperature of a developer is provided. The system includes a plurality of optical fibers, each optical fiber directing radiation to respective portions of the developer. Radiation reflected from the respective portions are collected by a measuring system which processes the collected radiation. The reflected radiation are indicative of the temperature of the respective portions of the developer. The measuring system provides developer temperature related data to a processor which determines the temperature of the respective portions of the developer. The system also includes a plurality of heating devices; each heating device corresponds to a respective portion of the developer and provides for the heating thereof. The processor selectively controls the heating devices so as to regulate temperature of the respective portions of the developer.