| 摘要 |
PROBLEM TO BE SOLVED: To obtain a sure and stable contact state between a photoreceptor and a developing roller, even in the case a developing roller is composed of hard material. SOLUTION: This device is allowed to let the developing roller 11 held in contact with the flexible thin cylindrical photoreceptor 140 being rotary driven, and supported by a pair of cylindrical members 120 at both end parts 141, and a latent image on a surface thereof formed thereon, while to control its bitten quantityδ' by abutting roller 11b. When assuming a diameter of the photoreceptor as DO, linear expansion coefficience asαO, the diameter of a disk shaped member as DF, the linear expansion coefficience asαF, the diameter of the developing roller as DO, the linear expansion coefficience asαD, the diameter of the controlling member as DC, the linear expansion coefficience asαC, differential between the minimum value and the maximum value of the applicable ambient temp. of the device as T, and the bitten quantityδon the medium of the applicable ambient temp., the device is composed so as to satisfy the next numerical formula, 0.5|DF.αF-DO.αO+DC.αC-DD.αD|T /2<=δ. |
