| abstract |
There are disclosed a toner supply roller which is composed of a foamed elastic body, and has a compression spring constant of 0.25 to 5.0 N/mm, and preferably has the number of cells per a length of 25 mm being 50 to 1200 in the foamed elastic layer; a developing apparatus which is equipped with the above toner supply roller and capable of affording images free from defect such as unevenness in pitch, density, etc.; another developing apparatus which is equipped with a toner supply roller and a developing roller, each being electroconductive, and which satisfies the requirement that the electric resistance of the toner supply roller is always lower than that of the developing roller at an impressed voltage of 100V to 500V, thereby enabling formation of satisfactory images by favorable electrification with the toner supply roller due to favorable adsorption of a toner onto the developing roller; and an image formation apparatus equipped with any of the above developing apparatuses. |