Abstract: The development apparatus that develops an electrostatic latent image formed on an image carrier comprises: a developer roller operable to carry toner on a circumferential surface thereof and develop the electrostatic latent image using the toner; a supply roller operable to perform toner supply to the developer roller; a voltage applier operable to apply a bias voltage V1 to the developer roller and apply a bias voltage V2 to the supply roller; and a controller operable to control the voltage applier in a toner compulsive consumption mode so that a value obtained by subtracting an average S2 of the bias voltage V2 per unit time from an average S1 of the bias voltage V1 per unit time indicates the same polarity as a normal charging polarity of the toner. Here, the toner compulsive consumption mode performs development to compulsively consume the toner carried on the circumferential surface of the developer roller.

Abstract: A developing device has a developer bearing member, a housing adapted to accommodate a developer, and a supply roller adapted to supply the developer within the housing for the developer bearing member. The supply roller has an outer circumferencial foam layer made of resin or rubber. The foam layer has an air permeability of 150-200 ml/cm2/s, a hardness of 50-200 N, and an average cell density of 20-40 per 25 mm width.

Abstract: An image forming apparatus has an electrostatic latent image bearing member capable of bearing an electrostatic latent image thereon, and a developer apparatus having a developer material for visualizing the electrostatic latent image into a visualized image. The developer apparatus includes a developer material bearing member, a housing adapted to accommodate a developer material, and a supply roller adapted to supply the developer material within the housing for the developer material bearing member. The supply roller has an outer circumferencial foam layer. The foam layer is made of resin foam or rubber foam and has an air permeability of 5 ml/cm2/s or less, a density of 50-200 kg/m3, and a hysteresis loss ratio of 35-45 %.

Abstract: A developing device has a bearing member that can bear a toner, a storing chamber for storing the toner, a waiting chamber disposed below the storing chamber for receiving the bearing member that can be filled with the toner and a buffer chamber positioned between the storing chamber and the waiting chamber for storing the developer material. A first horizontal connecting path connects upper portions of the storing and buffer chambers, and two second connecting paths connect lower portions of the buffer chamber and the waiting chamber. A feed member feeds toner from the storing chamber through the first connecting path into the buffer chamber. A first conveying member in the buffer chamber conveys the toner from one of the connecting paths to the other of the connecting paths, and a second conveying member in the waiting chamber conveys the toner within the waiting chamber in the opposite direction.