Developing cartridge and image forming apparatus

摘要

A cartridge detachably mountable to the main assembly of an image forming apparatus includes a developing frame provided with an opening; a developer carrying member in the opening to carry developer; a developer containing portion for storing developer, the developer containing portion supplying developer to the developing frame through the developer supplying opening; a sealing member for removably sealing the developer supplying opening; and a driving source substantially exclusive for providing the force for opening the sealing member.