Developing-unit shifting apparatus with two speed cooling fan

摘要

A developing-unit shifting apparatus has a photoconductive drum. A latent image corresponding to an original image is formed on the drum, and is developed by means of a first or second developing unit. These developing units are supported so that they can be associated with and disengaged from the drum. In the beginning of the copying operation, the first or second developing unit is affected so as to engage the drum. At the end of the copying operation, both these developing units are separated from the drum.