Patent attributes
A developing device includes: a developer carrier that carries toner thereon; a toner supply member that supplies toner to the developer carrier; a development chamber having the developer carrier and the toner supply member; a replaceable toner cartridge that supplies toner to the development chamber and collects toner from the development chamber; and a contact member that is in contact with the toner supply member to form a nip portion. At the time of replacement to the toner cartridge that contains new toner therein, the new toner is supplied from the toner cartridge into the development chamber and is made to pass through a nip portion between the toner supply member and the contact member within the development chamber, and then nip-passed toner is collected from the development chamber into the toner cartridge.