| 摘要 |
PROBLEM TO BE SOLVED: To effectively prevent the occurrence of electrifying noise by setting a specific difference of the JIS C hardness of a conductive elastic layer and the JIS A hardness of a resistance adjustment layer. SOLUTION: An electrifying roll 1 is used for electrifying a photoreceptor drum in an electrophotographic process and is provided on the outer periphery of its shaft 2 with a conductive elastic layer 3 and also on the outer periphery of it with a resistance adjustment layer 4. The JIS C hardness of the conductive elastic layer 3 with a relatively low hardness and the JIS A hardness of the resistance adjustment layer 4 with a relatively high hardness are set so as to make a difference of 75 degrees or more between their hardnesses. By making the hardness of the outer layer of the electrifying roll 1 relatively high and that of the inner layer of electrifying roll 1 relatively low, the vibration of the high-hardness outer layer of the electrifying roll 1 is preferentially absorbed in the soft inner layer of the electrifying roll 1 rather than transmitted to a photoreceptor drum which is a rigid body. Thus, the occurrence of electrifying noise is prevented.
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