| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing device capable of maintaining an appropriate toner charge amount, capable of giving good image properties over a prolonged period of time, and capable of suppressing toner flying-off and toner deposition on a developing roller. SOLUTION: The developing device has: a developer comprising a magnetic toner and a magnetic carrier; a magnetic roller 16 which forms a brush of the developer; the developing roller 17 which forms a thin layer of the magnetic toner; and a photoreceptor 19 which holds an electrostatic latent image. In developing device, the magnetic roller 16 and the photoreceptor 19 are kept away from each other, the magnetic toner is made to fly to a surface of the photoreceptor to develop the electrostatic latent image, after the development, the voltage between the magnetic roller 16 and the developing roller 17 is varied to release a thin toner layer from the developing roller 17, and a fresh thin toner layer is formed again on the developing roller 17. A magnetic powder has been incorporated into the magnetic toner particles, the magnetic powder has an average particle diameter of 0.01-0.50μm and an octahedron shape, each vertex and edge of the octahedron have a curved surface shape, and the magnetic powder has straight line portions at the periphery of a projected image of the octahedron. COPYRIGHT: (C)2006,JPO&NCIPI |
