An image forming apparatus includes an option device, the option device is coupled with a lower surface of an apparatus main body. A second connector is configured to be displaced between a first position and a second position. A push portion is configured to be pressed toward an inside of the option device when the option device is coupled with the lower surface. A link portion is pivotably supported, coupled with both the push portion and the second connector, and configured to, interlocking with the push portion being pressed, cause the second connector to be displaced from second position to first position. A first coupling portion couples the push portion with the link portion. A second coupling portion is configured to couple the second connector with the link portion. The first coupling portion and/or the second coupling portion is configured to release the coupling with the link portion.

An image forming apparatus includes an opening and closing unit attached to an image forming apparatus body. The opening and closing unit includes: an exterior member pivotably attached to the image forming apparatus body via a first shaft; a base member provided inside the exterior member and pivotably attached to the image forming apparatus body via a second shaft so as to be able to move with the exterior member; and an extension member attached to the base member in a manner capable of being pulled out and retracted.

When waiting for printing, a cam that rotates together with the rotation of a gear locks a knurl at position on the upstream side in the sheet conveyance direction, which prevents sheets from dropping down. Moreover, during printing, when the cam is rotated 180 from the locked position, the knurl is in a state capable of sliding toward the downstream side. As a result, with the force that returns the knurl to the upstream side being too small, it is possible to prevent feeding overlapping sheet due to the front end of a sheet further on the down side than a sheet being fed from dropping toward the downstream side further than the knurl.