Abstract: According to an image forming apparatus of the present invention, a developer filling opening is formed in an end of a casing which is provided with a developer-filled section, a holder section is arranged round the developer filling opening to hold a developer cartridge, guides are arranged adjacent to the developer cartridge holder section to guide the developer cartridge to the developer cartridge holder section when it is inserted into a developing unit from one side thereof, and the developer cartridge is attached to the developer cartridge holder section, when the developer-filled section with developer D in the developer cartridge, said developer consisting of toner T and carrier C mixed at a predetermined rate. The filling of developer or toner can be therefore more easily and quickly achieved without detaching the developing unit from the image forming apparatus.

Abstract: Disclosed is a developing device, which develops an electrostatic latent image by applying a toner thereto. The device is provided with an auto-toner adjuster, which detects the toner content of a developing agent, and resupplies the toner in accordance with the detected value, thereby keeping the toner content constantly at a predetermined value. At the shipment from the factory, the developing device is sealed hermetically, storing the developing agent used in setting the toner content by the toner adjuster.

Abstract: An image forming apparatus with an operation panel control function, the apparatus has a housing including an original scanning section for optically scanning an original placed on an original table so as to obtain optical image data, an image forming section for transferring the optical image data obtained by the original scanning section onto an image forming medium, an operation panel arranged on the housing and having an operation section for supplying various operation instructions to the original scanning section and the image forming section included in the housing, an operation data supply section which is detachably mounted on the operation panel, stores operation data associated with the various operation instructions, and has a data recording medium from which the storage data can be read out as desired, a display section which is arranged on the operation panel and can display at least the operation data written in the data recording medium of the operation data supply section, and a control secti