An image forming apparatus includes a transfer belt onto which a toner image formed on an outer surface of a photosensitive medium is transferred. In the drum coupling system, a coupling structure for the various marching drums to the respective marching carriers and a coupling structure for the various marching drums to the respective drum stands are the same. A membrane seals the reservoir, and a plunger impinges upon the membrane. Upon successful completion of the first designated change, a notification manager is used to issue a notification of the designated change to the flight plan trajectory.