An image forming apparatus includes a plurality of image forming cartridges removably mounted to an apparatus body one above the other and a transfer belt support unit hingedly attached to the image forming apparatus that is movable between a first position covering the plurality of image forming cartridges and a second position uncovering the plurality of image forming cartridges. Each image forming cartridge can be mounted to or dismounted from the image forming apparatus when the transfer belt support unit is in the second position. At least one of the image forming cartridges can be mounted to or dismounted from the image forming apparatus in a direction other than along an axis of rotation of a photoconductive member located in an image forming member.