A developing device usable with a main assembly of an electrophotographic image
forming apparatus includes a developing member for supplying a developer to an
electrophotographic photosensitive member for developing an electrostatic latent
image formed on the electrophotographic photosensitive member, a first electrode,
and a second electrode. An electrical signal is generated in accordance with an
electrostatic capacity between the first electrode and second electrode when the
first electrode or the second electrode is supplied with a voltage from the main
assembly of the electrophotographic image forming apparatus, and is measured by
the main assembly of the electrophotographic image forming apparatus to detect
a remaining amount of the developer.
