Image forming apparatus capable of determining whether toner cartridge is attached to appropriate slot provided in main casing

An image forming apparatus comprising:

• a drum cartridge to which a toner cartridge is attachable, the toner cartridge accommodating therein toner, the drum cartridge including a photosensitive drum and a drum memory storing therein drum information relating to the photosensitive drum;
• a frame, the drum cartridge being attachable to the frame in a state where the toner cartridge is attached to the drum cartridge;
• and
• a controller including a control memory and a processor, the control memory storing therein first information, the drum memory being configured to store the first information,
• the processor being configured to perform:
• in a state where the drum cartridge is attached to the frame,
• (a) reading information from the drum memory;
• (b) determining whether the information read in the (a) reading includes the first information;
• and
• in response to determination in the (b) determining that the information read in the (a) reading does not include the first information, (c) writing, into the drum memory, the first information stored in the control memory.