DEVELOPING DEVICE

PURPOSE:To make an image free from abnormality even after continuous copying and to obtain image quality comparable to that in the early stage of copying by impressing bias on a toner feeding member surfacecoated with a specified fluorine compd. so that the member has higher positive potential than a toner conveying member. CONSTITUTION:A developing device is fitted with a toner conveying member, a toner layer thickness regulating member and a toner feeding member freely rotatably supported while in contact with the toner conveying member and used for feeding a toner onto the conveying member. The surface of the toner feeding member is coated with at least one kind of arom. fluorine compd. selected among compds. represented by formulae I, II, etc., and bias is impressed on the toner feeding member so that the member has higher positive potential than the toner conveying member by 0-500V. In the formulae I, II each of R1-R4 is H, Cl, etc., Rf is CnF2n+1 or OCnF2n+1 and n is a positive integer. In the case of negative potential, the toner is not satisfactorily shifted onto the conveying member. In the case of >=+500V, toner filming is caused on the conveying member and ground fog is caused on an image.