ELECTROSTATIC DUST REPELLER FOR ELECTROPHOTOGRAPHIC APPARATUS

摘要

In a dry toner developing system (38) for an electrostatic copier (10), the toner particles (40) tend to scatter to other portions of the apparatus such as the bearings and gear trains and even onto the copy sheet itself thereby making for an unreliable and relatively dirty apparatus. The problem of toner scattering is especially critical in high speed printers due to the high rotational speed of the magnetic roll (38) which produces air turbulence that tends to scatter the toner particles (40) to other portions of the copier (10). In order to prevent toner scattering, the present device has a pair of electrically charged members (20, 22) disposed on opposite sides of the magnetic brush generating roll (38). The charged members (20, 22) are biased to the same polarity as the toner particles so that the toner particles (40) adjacent the edges of the roll (38) are repelled toward the magnetic brush area (42) thereby eliminating toner scattering.