A developer supplying device including a developer holding unit configured to hold a developer, a developer transfer device configured to electrostatically transfer the developer from the developer holding unit, and a charging member having holes piercing therethrough from the developer holding unit,...http://www.google.com.au/patents/US7181155?utm_source=gb-gplus-sharePatent US7181155 - Developer supplying device, developing roller, developing device, image forming apparatus and process cartridge
