IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To provide an image forming apparatus which is capable of suppressing white spots occurring in an initial image after the start of operation and preventing image defects due to contamination of a charging member after the lapse of time.SOLUTION: An image forming apparatus includes: a charging roller which has, on a resistance elastic layer, a surface layer having surface roughness Rz of 3 to 6 μm in an initial stage after the start of operation and has an absolute value of an impedance ratio of 0.81 or lower at a frequency of 800 to 3,000 Hz and has the surface roughness Rz of the surface layer reduced by an amount Rz of 0.1 to 4 μm after the lapse of a prescribed time; and a photoreceptor drum which has a film thickness D of 20 to 40 μm in the initial stage after the start of operation and has the film thickness D reduced by an amount D of 5 to 25 μm after the lapse of a prescribed time. In this case, expression of 0.005≤ Rz/ D≤0.8 is satisfied, and the impedance ratio is expressed by ZE/(ZE+ZS) where ZE represents impedance of the resistance elastic layer and ZS represents impedance of the surface layer.