| 摘要 |
PURPOSE:To form a thin uniform layer of a developer by mixing magnetic particles coated with a substance having a critical surface tension not above a specified value with a nonmagnetic developer in a magnetic field to triboelectrify the developer, forming a magnetic brush, and applying the developer on the surface of a holding member with said brush. CONSTITUTION:A sleeve 2 rotates in the direction of arrow (b) opposite to a photosensitive drum 1 rotating in the direction of arrow (a), and a magnet 7c is arranged in the sleeve 2. A nonmagnetic developer 4 is mixed with magnetic particles 5 coated with a substance having a critical surface tension gammac<=30 dyne/cm, such as polyvinyl fluoride, and placed into a hopper 3. A magnetic brush 8 of the particles 5 is formed in a magnetic field caused between the magnetic pole of the magnet 7c and a magnetic blade 6, the developer 4 is triboelectrified by mixing it with the particles 5, and the triboelectrified developer 4 is uniformly and thinly applied on the surface of the sleeve 2 with the magnetic brush 8 by image force. |
