Abstract: Provided is a method for conveniently producing a water dispersion of oxidized carbon black particles that exhibits excellent dispersibility and storage stability, in the case of producing a water dispersion of oxidized carbon black particles by liquid-phase oxidation of carbon black particles using a persulfate. In the method for producing a water dispersion of oxidized carbon black particles by bringing at least one persulfate and carbon black particles into contact to perform liquid-phase oxidation, in the presence of an inorganic alkali in an amount equal to or greater than an amount theoretically necessary for neutralizing an acidic product produced by the liquid-phase oxidation, the persulfate and the carbon black particles are brought into contact in water and subjected to liquid-phase oxidation treatment while being heated.

Abstract: In this electronic endoscope apparatus, a waveform compensating device compensating the waveform of a driving pulse applied to a solid state imaging device is provided within a light source connector, an information signal generating device generating an information signal relating to the kind of the electronic endoscope is provided within a signal connector and a selecting device decoding the above mentioned information signal and outputting a control signal to a video signal processing circuit device is provided within a control device.