The invention provides an electronic photographing apparatus using a two-component developer as a mixture of a toner and a carrier as well as a development unit including a developer roll having magnetic poles therein. The closure shaft has a coupler part configured to be coupled to and uncoupled from a drive shaft of the drive device. The third planetary gear set has a first member connected with the input shaft and a second member is connected with the output shaft. The gel pad permits flexible instrument placement, as well as translational and angular degrees of freedom for the instruments while maintaining a gas tight seal.