Electrostatic record developing apparatus

Claim 1

An electrostatic record developing apparatus comprising a hollow cylindrical rotary member of nonmagnetic material, means for causing rotation of said hollow cylindrical rotary member, a cylindrical permanent magnet disposed coaxially within said hollow cylindrical rotary member so as to be rotatable relative to said hollow cylindrical rotary member, said cylindrical permanent magnet being formed in a body having an odd number of magnetic poles and more than three magnetic poles extending in strip form in the axial direction thereof, said strip-like magnetic poles being arranged with alternating north poles and south poles except for one portion of the cylindrical body at which two adjacent magnetic poles of the same polarity are arranged for producing a repulsive force which effectuates the removal of developer from the surface of said cylindrical rotary member, means for feeding an electrostatic recording sheet relative to said hollow cylindrical rotary member, means for adjustably fixing said cylindrical permanent magnet in such a position that one of the magnetic poles is disposed opposite to the image carrying surface of the electrostatic recording sheet and the adjacent magnetic poles of the same polarity are disposed on the trailing side of the electrostatic recording sheet, and means for supplying a powdery developer to the surface of said hollow cylindrical rotary member so that the powdery developer is attracted to and forms a magnetic brush on the surface of said hollow rotary cylindrical member thereby developing a latent electrostatic image recorded on the image carrying surface of the electrostatic recording sheet.