Patent ID: 7016630

Claim:
An image forming apparatus comprising: a powder transport mechanism including a powder container and a powder transport means, which is rotatable relative to said powder container, wherein said powder transport means has a rotation center substantially on an axis of said powder container, a space between an inner wall surface of said powder container and said powder transport means is sealed with magnetic particles held by a magnetic-field generation means, and said magnetic particles have a saturation magnetization σs in a range of 30.0 to 80.0 Am 2 /kg and a value of A×σ A in a range of 3,000 to 35,000, where a residual magnetic flux density of said magnetic-filed generation means is represented by A mT and a magnetization intensity of the magnetic particles in a magnetic field with the residual magnetic flux density A mT is represented by σ A Am 2 /kg, provided that A is within a range of 50 to 1,000 mT.