Apparatus for controlling the amount of developer material and toner concentration

摘要

A developing apparatus is provided in which a developer material in a development tank is made to circulate through a developer material storage vessel detachably mounted on the development tank, thereby prolonging the service life of the developer material. In the developing apparatus of the present invention, a predetermined developer material composed of a toner and a carrier stored in a development tank 31 is stirred by a stirring roller 33, and supplied to a latent image formed on a photoreceptor 11 by means of a development roller 32 in the development tank to visualize the latent image. The concentration of the toner consumed in the development tank is detected by a toner concentration sensor 34 so that toner is supplied from a toner storage tank 41 to the development tank so as to maintain the concentration of the toner at a constant level. In this case, a developer material conveyor shaft 37a discharges the developer material from the development tank to a developer material storage vessel 50, and a developer material conveyor shaft 37b makes the developers material received from the developer material storage tank into the development tank thereby to control the amount of developer material and the concentration of the toner in the development tank to be constant. The developer material storage vessel is replaced with a new one at proper times so as to gradually refresh the developer material therein.