| 摘要 |
An image forming apparatus includes an image bearing member on which an electrostatic latent image is to be formed; and a developing device for developing the electrostatic latent image by supplying a developer to the image bearing member. The developing device includes a developer container for containing the developer; a rotatable developer carrying member, including a first electrode member, for carrying and supplying the developer to the image bearing member; and a developer supplying member, which is provided in contact with the developer carrying member and includes a surface foam layer and a second electrode member for rotatably supporting the developer supplying member, for supplying the developer to the developer carrying member. The apparatus further includes a measuring device capable of measuring a remaining developer amount in the developer container by detecting electrostatic capacity between the first electrode member and the second electrode member; and a replenishing device for performing a replenishing operation for replenishing the developer supplying roller with the developer by rotating the developer supplying member while applying a DC bias between the first electrode member and the second electrode member so that a value obtained by subtracting an electric potential of the second electrode member from an electric potential of the first electrode member has an identical polarity to a normal charge polarity of the developer. When the remaining developer amount measured by the measuring device is not more than a threshold, the replenishing operation is performed by the replenishing device and thereafter the remaining developer amount is measured again by the measuring device. |
