An image forming apparatus having removable/replaceable process cartridges is provided. One of the removable/replaceable process cartridges may be removed/replaced from a panel which is different than a panel from which the other removable/replaceable process cartridges may be removed/replaced. One of the removable/replaceable process cartridges may be associated with an exposure device which is only used to expose a portion of that process cartridge while the other removable/replaceable process cartridges may be associated with at least one other exposure device. An image forming apparatus may include two or more different types of exposure devices (e.g., laser based, light emitting diode based, etc.). An image forming apparatus may include a plurality of guide members for guiding portions of an exposure device arranged on a panel of the image forming apparatus such that when the door or panel is arranged on the image forming apparatus, the exposure device is guided into position by the guide members.