| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing roller having a sleeve surface shape which prevents impairment of the ability of developer on a nonmagnetic sleeve to be carried and the ability of it to be separated off. SOLUTION: An electrophotographic developing roller has a magnet roller having fixed magnetic poles and a nonmagnetic sleeve 22 disposed coaxially in the position of the outside diameter of the magnet roller and rotated, carries developer, comprising magnetic carrier and insulating toner, while holding it on the sleeve, and develops an electrostatic latent image. In the surface of the nonmagnetic sleeve, axially extending, nearly V-shaped grooves 1 are provided at specific intervals in a circumferential direction. Two inner walls composing each of the nearly V-shaped grooves establish a relationship ofα<βwhereinαis an angle formed between the inner wall 1b situated in the reverse direction of the direction of the rotation of the sleeve and a straight line L connecting the top of the nearly V-shaped groove and the center point of the sleeve andβis an angle formed between the inner wall 1a situated in the direction of the rotation of the sleeve and the straight line L. |
