Patent ID: 7454154

Claim:
An image forming device comprising: an image carrier that rotates by receiving driving force; a charging roller that abuts and charges the image carrier, the charging roller including a shaft that is rotatably supported; and a cleaning roller that abuts and cleans the charging roller, the cleaning roller including a shaft that is rotatably supported, and a porous elastic layer being provided around the shaft; wherein the image forming device satisfies the relation T×α/ 100>( R 1+ R 2)− L>B> 0 where L [mm] is a separation distance of axial centers of both end portions of the shaft of the cleaning roller and the shaft of the charging roller, R1[mm] is a radius of the charging roller, T [mm] is a thickness of the porous elastic layer, R2[mm] is a radius of the cleaning roller, B [mm] is a flexure amount of an axial direction central portion of the shaft of the cleaning roller, and α [%] is a maximum allowable compression rate in accordance with a stress-flexure curve when compressing the porous elastic layer with an applied stress which is 200% of an average stress P [kPa], the average stress P [kPa] being an average value of stresses at compression rates of the porous elastic layer of 10% to 40%.