摘要:
A development apparatus (40) includes a housing (48) defining a chamber (46) holding a supply of two-component developer material consisting of toner, and magnetizable carrier beads. The development apparatus also includes an extended life, increased reliability magnetic roll assembly within the housing for repeatably transporting a desired quantity of attracted developer material, fed from the chamber, for movement through the development zone. The improved magnetic roll assembly (50; Fig.2) includes a rotatable non-conductive shell or substrate (90; Fig.2) surrounding a magnetic member (M1-M4; Fig.2) so as to prevent the creation of eddy currents in the substrate during its rotation. The substrate has an elastomeric coating layer formed (100; Fig.2) over it. The elastomeric coating layer has a mechanically deformable smooth surface (102; Fig.2) for effectively holding, even at relatively high rates of speed, the quantity of attracted developer material thereon being transported. The smooth surface is deformable by magnetized carrier beads acting under the influence of the magnetic member.