Developing device for use in electrophotography

Claim 1

A developing device for use in electrophotography wherein a toner is applied to an electrostatical latent image supported on the surface of a member to make the image visible, comprising a rotatable member bearing an electrostatic latent image thereon; a first magnetic roll disposed adjacent to the member which comprises a rotational tube of non-magnetic material and a cylindrical fixed magnet body located in the tube and having more than two magnetic poles spaced from each other wherein one of the poles is located adjacent the surface of said member, said pole serving as a developing pole; a second magnet roll disposed adjacent to the member and adjacent to the first magnet roll, and a developer storing chamber, said second magnet roll comprising a rotational tube of non-magnetic material and a cylindrical fixed magnet body located in the tube and having more than two magnetic poles longitudinally arranged thereon wherein one of the poles is located adjacent to the surface of said member, another of said poles is located adjacent to the first magnet roll and another of said poles being immersed in said developer storing chamber; the tubes of the first and second magnet rolls being rotated such that the surfaces of said tubes move in the same direction with respect to each other at the point at which said tubes are adjacent to each other, the surface of said member being translated in the same direction as the tube of said second magnet roll at the location where the tube of the second magnet roll and the surface of said member are adjacent to each other, the developer being carried from the developer storing chamber to the portion of the first magnet roll opposite said member, the carrier particles adhered on the member being removed from said surface by the magnetic pole of the second magnet roll adjacent the surface of said member.