Abstract: A device for detecting a body comprises transmitter means, receiver means for receiving the signal from the transmitter means, means for setting the level of a reference signal by the reception signal from the receiver means provided when the body is in a reference condition, to correct the reference signal, which reference signal provides a reference for identifying the reception signal, and comparator means for identifying the reception signal in accordance with the reference level connected to the reference level setting means. The body detecting device effects the detection by the output of the comparator means.

Abstract: There is disclosed a safety device in a copying machine for detecting jamming of copying sheet materials to remove power only from the machine elements which might cause damage during subsequent operation of the machine. The copying machine is provided with a jam detector, a jam indicator to let a machine operator know of an occurrence of jamming, a disconnecting unit for operation in response to a signal from the jam detector to remove power from heaters, high voltage circuits, and other critical elements in the machine, and a jam indicator activating unit for operation in response to a signal from the disconnecting unit for activating the jam indicator after the lapse of a certain fixed period of time after receiving the signal.

Abstract: There is disclosed a method of maintaining at a desired level the temperature of components in a copying machine which is in its idle state. An electric power is supplied members in the machine having an impedance component after the copying operation has been stopped. The voltage of the power must be set at a value lower than the rated voltage of the members.

Abstract: A temperature control system comprises a heat sink heatable upon application of electric power thereto, an AC power source for heating the heat sink, temperature detector means for detecting the temperature of the heat sink, and control means for controlling the electric power applied to the heat sink in accordance with an output signal from the detector means so that the heat sink maintains its required temperature. The control means is operable to cause application of a full power of the power source to the heat sink at the initial heating stage thereof and application of a partial power of the power source to the heat sink when the temperature thereof is in the vicinity of the required temperature.