Patent ID: 8811833

Claim:
An image forming apparatus comprising: a developing device including a container that has an opening and contains a toner, a toner bearing member arranged at the opening of the container, having a first electrode member, and supplying an electrostatic latent image with the toner by bearing and conveying the toner, and a toner supply member arranged in the container and having a second electrode member and a foam layer, wherein the foam layer is provided around the second electrode member, wherein the developing device supplies the toner bearing member with the toner in the container by rotating the toner supply member in a contact manner with the toner bearing member; a detection mode execution unit configured to execute a detection mode in which a predetermined period for changing a toner amount in the foam layer by rotating the toner supply member is provided, a capacitance C 1 between the first and second electrode members is detected before the predetermined period, and a capacitance C 2 between the first and second electrode members is detected after the predetermined period; and a notice signal generating unit configured to generate a notice signal in response to an absolute value |C 1 −C 2 | of a difference between the capacitances C 1 and C 2 being smaller than a predetermined threshold, wherein the notice signal is indicative of a toner amount in the container being smaller than a predetermined amount.