| 摘要 |
PURPOSE:To obtain a good picture quality by providing a first magnetic field generating means for leading a magnetic grain on a sleeve, to a developing part, a developer adjusting material on the upstream side of a rotation of the sleeve, and also, a second magnetic field generating means on the upper stream, and allowing the maximum magnetic field to oppose the guide face of a developer circulation limiting member. CONSTITUTION:A developer adjusting material 24 and a circulation limiting material 26 are formed integrally, and the guide face 261 of the member 26 has the length of about 5-15mm, and positioned at both sides of the vertical face Q of the upper part of a horizontal plane (l) passing through the rotation center OS of a sleeve 22. The member 24 is in a second quadrant formed by the plane (l) and Q, has an end part 241 separated by a size d2 from the surface of the sleeve, and an angle made by the guide face 261 against the contact surface P of the opposed sleeve surface is set to 0<rho<=45 deg.. The magnetic pole 23a of >=600 cgs is provided by inclining it by beta>5 deg. against the upstream with regard to the center OS, the member 26 has a magnetic material at the side of a non-magnetic member 24, and the magnetic pole 23a is in the upstream side of this magnetic material. When the sleeve 22 is rotated (b), and the volume ratio of the magnetic grain of a developer carried to a space formed by an electrostatic latent image carrying body and the sleeve is selected as 1.5-30%, a good copy picture quality is obtained. |
