Patent ID: 7925175
Filing Date: 2011-04-12
Classification: G03G

Abstract:
1. A developing device comprising: a developer container configured to store a developer containing a carrier and a toner; a developer supplying member configured to supply the toner stored in the developer container to an image bearing member; voltage applying means capable of applying a bias voltage to the developer supplying member; image density detecting means configured to detect a density of toner formed on the image bearing member; and control means configured to correct a toner concentration in the developer on the basis of a result of image density detection of a reference toner image formed on the image bearing member, the image density detection being performed by the image density detecting means, wherein the control means is capable of executing a first toner concentration correction between printing operations and executing a second toner concentration correction between predetermined points during continuous printing; the first toner concentration correction includes applying a predetermined reference-toner-image formation bias voltage to the developer supplying member so as to form the reference toner image, the reference-toner-image formation bias voltage being a voltage for forming the reference toner image; and the second toner concentration correction includes applying the reference-toner-image formation bias voltage and a correction bias voltage to the developer supplying member so as to form the reference toner image.