| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a developing unit which can suppress the amount of sticking carriers and obtain high quality images by setting an upper limit to the magnetic flux density forming magnetic brushes to obtain high quality images besides the conditions for the magnetic attraction to prevent the carriers from sticking. <P>SOLUTION: In this developing unit, the component Br of the magnetic flux density normal to the development sleeve of the developing unit composed of a non-magnetic developing sleeve and the magnetic poles fixed in the developing sleeve satisfies 92≤Br≤160(mT) inside the developing nip area, and the A defined in expression (1): A=Br(the partial derivative of Br with respect to r)+(Bθ/r)(the partial derivative of Br with respect toθ), satisfies 9.0≤A≤18.0 (T<SP>2</SP>/m). Thus, it is possible to suppress the amount of sticking carriers and to obtain high quality images. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
