| abstract |
A developing roller has a core bar, an electrically conductive layer formed on the circumferential surface of the core bar, and a covering layer formed on the circumferential surface of the conductive layer. The covering layer includes a reaction product produced by subjecting a reaction mixture containing a polyol, an isocyanate compound and a both-terminal reactive silicone oil to a reaction condition for them, and has a dynamic friction coefficient against paper of 0.9 or more and less than 1.2. |