PURPOSE: To prevent the soiling of an electrifying roller with toner and simultaneously, the generation of a lateral streak like abnormal image.

CONSTITUTION: In this roller electrifying device applying a voltage to the electrifying roller 101b brought into contact with the surface of a photosensitive drum 103 and rotated, to electrify a solid stearyl acid zinc 102a as a lubricating oil additive coating means coating the surface of the electrifying roller 101b with stearyl acid zinc 102a (a lubricating oil additive) is provided. Moreover, the solid stearyl acid zinc 102 is pressed with small pressure in a degree that the rotation of the electrifying roller 101b is not disturbed, by a prescribed spring mechanism (not shown in the figure).