PURPOSE: To eliminate defective electrostatic charging and a defect in an outputted image caused by the staining of an electrostatic charging member such as darkish and black stripes under the environment in high temp. and high humidity by impressing an AC voltage ≥ specified times as high as a normal one on the electrostatic charging member before an image is formed, when the image is formed, and between papers, etc.

CONSTITUTION: The electrostatic charging blade 6 as a fixed contact electrostatic charging member is fixed and supported by a supporting part while the surface of a 1st resistor layer 4 is made to face a photoreseptive drum 8 and to abut on the photoreceptive drum 8 by a prescribed pressing force. An electrostatic charging bias is impressed on the metallic plate electrode 2 of the blade 6 by a power supply 7, then, the surface part of the photoreceptive drum at the abutting nip part 11 between the blade 6 and the photoreceptive drum 8 is electrostatically charged, the photoreceptive drum surface at the nip part 11 is renewed and moved in accordance with the rotation of the photoreceptive drum 8, so that the whole photoreceptive layer 9 is electrostatically charged. And in this control method, the AC voltage ≥1.1 times as high as the normal voltage, preferably, the AC voltage ≥1.2 times is impressed on the electrostatic charging blade 6 before the image is formed, when the image is formed, and between the papers, etc.