| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that, if an image forming unit is left idle for a long period of time, press-contact marks occur on an abutting surface between a charge roller and a photoreceptor drum to cause a charge failure.SOLUTION: The image forming unit 10 includes a rotatable photoreceptor drum 13, a charge roller 20 positioned to contact the photoreceptor drum 13 and charge a surface of the photoreceptor drum 13, and a developing part, which supplies toner 12 to the photoreceptor drum 13 for obtaining the image. The charge roller 20 has a shaft 21, a conductive base layer 22 provided around the shaft 21, and a surface layer 23 formed on a circumferential surface of the conductive base layer 22. The surface layer 23 contains particles having an average particle size of 5 μm to 20 μm, in a dispersed manner, and a value of surface area per unit area of the surface layer is in a range from 1.5 to 3.0. |
