Abstract: An image forming apparatus such as a copying apparatus and a laser beam printer, is capable of forming a superimposed image or duplex image on one sheet. The sheet which has been once subjected to the image forming operation and which is going to be subjected to another image forming operation is reintroduced into the image forming station selectively through a flow-through sheet passage or through an intermediate tray on which the transfer sheets are once stacked. A displaceable flapper is provided to direct the sheet selectively to the flow-through passage or to the intermediate tray.

Abstract: An image forming apparatus includes a plurality of the developing devices for developing the latent image formed on an image bearing member. The plural developing devices are each movable between its developing position for developing the latent image on the image bearing member and its retracted position away from the image bearing member. The image forming apparatus includes a shutter for selectively opening and closing the developing aperture of the developing device of one of the developing devices. The shutter opens and closes the developing aperture of said one of the developing devices in association with movement of the other developing device between the developing position and the retracted position.