Developing unit including a partition wall defining a non-agitation space in a developer container

摘要

A developing unit comprises a developer container having an agitation space for agitating developer therein and a toner hopper for feeding toner to the agitation space of the developer container. A lower wall of the toner hopper includes a toner drop port allowing toner to fall into the aforesaid agitation space. On a surface of the lower wall exposed to the agitation space, disposed is a partition wall surrounding the periphery of the toner drop port. The partition wall defines a non-agitation space. The toner is allowed to fall from the toner drop port smoothly into the agitation space through the non-agitation space which is not affected by the agitation.