In case the output of an antenna member does not return to a first level even
after an execution of a toner replenishing operation for a predetermined period
from a state where an image forming operation is prohibited, the toner replenishing
operation is terminated. Such configuration avoids an unnecessary idle rotation
of a developing device at the replacement of the developing device or in case an
empty toner cartridge is mounted again on an image forming apparatus, thereby suppressing
drawbacks such as an image fog or an image density loss.
