| 摘要 |
<p>A development appts. for developing a latent image recorded on an image bearing member comprises a housing storing a magnetisable two-component developer including toner particles and magnetisable carrier beads, and a feeder assembly for transporting the developer from a mixing chamber to the development zone and comprising a movable substrate having first and second surfaces and a path of movement through the mixing chamber, a magnetic member adjacent the path of movement and the first substrate surface and generating a strong magnetic field about a first point along the path of movement, and a thin elastomeric coating formed on the second substrate surface and having a smooth surface for holding magnetic developer attracted thereto at the first point, the smooth surface being mechanically deformable by magnetised carrier beads acting under the strong magnetic field to form depressions for frictionally holding the developer during transportation. Also claimed is the feeder assembly itself in the form of a magnetic roll assembly. Pref. the appts. includes a movable donor member, pref. a rotatable roll, mounted for receiving charged toner particles from the elastomeric coating and moving them through a development zone for developing the latent image. The path of movement of the movable substrate is continuous and surrounds the magnetic member. The movable substrate is a rigid cylindrical shell rotatable about the magnetic member. This shell has a modulus of elasticity, E, of greater than 300,000 lbs/in2, and is 475 mm long with a centre of deflection of 0.0016 ins. when laden with developer. The movable substrate comprises an electrically non-conductive material, esp. a general purpose polycarbonate material, or a urethane based polyester material having a modulus of elasticity of 300,000 lbs/in2 and a resistivity of 108 ohm.cm.</p> |
