DEVELOPING DEVICE, PROCESS CARTRIDGE AND IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To realize a developing device in which a problem of a toner concentration distribution in a two-component developer may be satisfactorily reduced or overcome.SOLUTION: A developing device comprises: a supply conveyance path including a supplying/conveying member 5b for conveying a two-component developer in an axial direction to supply it to a developer carrier; a stir conveyance path disposed adjacently to the supply conveyance path with a partition plate 5d disposed therebetween and including a stirring/conveying member 5c for stirring the developer to which a toner has been supplemented to convey the developer in a direction opposite to the axial direction; and opening merging accelerating means for sending, through a dividing opening 5f provided in the partition plate 5d, the two-component developer present on a side of the stir conveyance path toward the supply conveyance path and sending the two-component developer present on a side of the supply conveyance path toward the stir conveyance path. The opening merging accelerating means includes an impeller 5g having an opening rotation axis 5g1 provided in the dividing opening 5f and one or more planer paddles 5g2 fixed on the rotation axis; and driving means for driving the impeller 5g.