Patent ID: 7386261
Filing Date: 2008-06-10
Classification: G03G

Abstract:
1. An image forming apparatus comprising: a developing device which develops an electrostatic image on an image bearing member with a developer including toner and carrier; a movable member which supports said developing device and is movable between a developing position at which said developing device is opposed to said image bearing member and a non-developing position at which said developing device is not opposed said image bearing member; a replenishment device which feeds a developer for replenishment to said developing device; a developer replenishment path which is supported by said movable member and allows the developer for replenishment to be fed from said replenishment device to said developing device; and a conveyance screw arranged within the developer replenishment path so as not to come into contact with an internal wall of the developer replenishment path, wherein X (g) representing a quantity of the developer for replenishment present in a clearance section between said developer replenishment path and said conveyance screw, Y (g) representing a quantity of the developer in said developing device, Q(μC/mg) representing an absolute value of a electric charge per unit weight of toner in said developing device, and A(μC/mg) representing an absolute value of a variation value of an electric charge per unit weight of the toner corrsponding to a 1% variation of a toner density value in the developer in said developing device, X (g), Y (g), Q(μC/mg) and A(μC/mg) satisfies a relationship of X≦(Y×Q)/(500×A).