| 摘要 |
PROBLEM TO BE SOLVED: To supply a long-life development roller which is low hardness and excellent in abrasion resistance, and to provide a development roller with small surface roughness.SOLUTION: A development roller has: a shaft being a central axis; an elastic layer covering an outer periphery of the shaft which is made of polyurethane elastomer that is polymerized by polyol composition containing trifunctional polyetherpolyol, in which number average molecular weight is 4500 to 5500 and a degree of unsaturation is 0.01 meq/g or less, by 50 to 80 wt.%, and trifunctional polyetherpolyol, in which number average molecular weight is 2500 to 3500 and a degree of unsaturation is 0.01 meq/g or less, by 50 to 20 wt.%, and polyisocyanate; and at least one layer of coating layer formed on the elastic layer. |
