Development apparatus and method using selectively applied AC voltages

摘要

A development apparatus according to the invention comprises at least two developer carrier members in juxtaposition for transporting a developer material to a development region between the developer carrier members and an image bearing member in opposed relation. An AC voltage applying device is adapted to apply AC voltages to the respective developer carrier members thereby applying AC electric fields to the respective gaps between the developer carrier members and the image bearing member based on an active period to apply the AC electric field and an inactive period to apply no AC electric field. When one of the adjacent developer carrier members is subject to the active period, the other developer carrier member is subject to the inactive period.