Abstract: An electrophotographic roller comprising a substrate and a foam layer on an outer peripheral surface of the substrate, the foam layer constituting an outer surface of the electrophotographic roller, the foam layer comprising cells each of which opens on the outer surface, and the foam layer having a zero-point charge measured using a standard carrier of 40 ?C/g or more.

Abstract: The present invention relates to an emergency supervisory system which comprises a plurality of supervisory apparatus provided for respective supervisory regions and connected in parallel with each other to signal lines derived from a central signal station; and switching devices which are provided at positions for separate the supervisory apparatus from each other and adapted to be closed normally and opened upon detection of short-circuiting to separate the supervisory apparatus adjacent thereto from the lines, thereby to supervise an emergency such as a fire through one or both of the signal lines.

Abstract: A fire alarm system having a plurality of ceiling fixtures containing ionization smoke detectors which are located in regions of a building to be protected. Each smoke detector is connected to a common fire alarm signal receiver for sounding an audible alarm as well as a visual alarm in response to a fire alarm signal therefrom. Each ionization smoke detector is also provided with an ionization ambient atmosphere auxiliary co-detector for producing an auxiliary signal which is responsive to the environmental conditions of the detector in situ. The ambient atmosphere detector comprises an internal circuit having female terminals of a receptacle mounted in the wall of the corresponding fixture, and an external circuit having male terminals of a plug adapted to mate with the corresponding female terminals of such receptacle.