Development efficiency in electrophotography

Two measures of development efficiency are defined for dual-component electrophotographic development systems based on the known physics of development. For the insulative magnetic brush development system, the efficiency measures the strength of the electric field as seen by toner particles. Experimentally it is shown that it is closely equal to the dielectric constant of the mix. Theoretical questions raised by this result are discussed. For the conductive magnetic brush development system, the efficiency is unity for an infinitely conductive system are decreases as the conductivity decreases. Therefore it is a measure of developer degradation.<
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