| 摘要 |
The magnet roll of the present invention includes a shaft and a permanent magnet member fixed to the shaft, the permanent magnet member being composed of a hollow, cylindrical magnet body, and a magnetic pole piece fixed to a recess of the hollow, cylindrical magnet body, the hollow, cylindrical magnet body having a plurality of axially extending magnetic poles arranged circumferentially on the surface, the magnetic pole piece being provided with two magnetic poles having the same polarity for constituting a developing magnetic pole, and a thermally demagnetized portion being formed substantially at a center of the developing magnetic pole such that the permanent magnet member generates a magnetic flux density distribution having two peaks of the same polarity at a position of the developing magnetic pole.
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