Develop unit, process cartridge, and image formation apparatus

A develop unit comprising:

• a developer support body comprising a cylindrical hollow body supporting a developer on its outer surface, a magnetic field generator contained in the hollow body and including a magnetic pole absorbing the developer onto the outer surface, the developer being made of a toner and a magnetic carrier;
• a developer supply path formed in parallel with an axial direction of the developer support body;
• a developer supply member disposed in the developer supply path and rotating to carry and supply the developer to the developer support body in the axial direction;
• and
• a bulkheading member forming the developer supply path with one end extending along the developer support body with a gap, wherein
• the magnetic pole is disposed in the magnetic field generator so that a normal line through a maximum magnetic flux density point in a circumferential direction coincides with a tangent line to an upper portion of the developer supply member in a rotary direction, the maximum magnetic flux density point being a point at which a density of a magnetic flux from the magnetic pole is maximum on an outer surface of the hollow body.