Abstract: A developing roller for use in an image forming apparatus using an electrophotographic process. The image forming apparatus includes a photosensitive drum having a transcribing roller cleaning device; the developing roller disposed between a transcribing device and an exposing device adjacent to the photosensitive drum, for frictionally charging toner at a place where the developing roller contacts with a supply roller and transferring the charged toner to a developing region so as to attach the charged toner to a latent image formed on the photosensitive drum; a regulating blade disposed between the developing region and the supply roller, for regulating a toner layer on the developing layer into a thin toner layer, being in contact with the developing roller; the supply roller in contact with the developing roller, for frictionally charging the toner transferred into a contact nip by a relative motion therebetween; and an agitator for transferring the toner in a toner cartridge to the supply roller.

Abstract: A developing device in an image forming apparatus having a cartridge loading portion for loading a replaceable toner cartridge, a frame including a hollow portion for receiving a developer supplied from the cartridge, a photosensitive drum installed in the hollow portion and having a surface exposed to the exterior of the frame, and a developer roller installed adjacent to the photosensitive drum, the developing device having a cartridge control device installed on the one side of the cartridge loading portion to control the installation and removal of the toner cartridge, in which the cartridge control device includes a cartridge installation and removal device for allowing a user to install or remove the toner cartridge, a counter for counting the number of toner cartridge replacements, and a cartridge removal protector for prohibiting removal of the toner cartridge from the developing device when a predetermined number of toner cartridge replacements is reached so as to prevent contamination resulted from

Abstract: The present invention provides a developing device of an electrophotographic recording system for developing an electrostatic latent image formed on a photosensitive drum. The developing device includes a hopper which stores toner and a developing roller which develops the electrostatic latent image formed on the photosensitive drum using the toner stored in the hopper. On one side of the hopper at a predetermined height from its bottom, a light-emitting element for emitting light is positioned. A toner detecting device detects the existence or non-existence of toner by using a light-receiving element positioned on the interior of the hopper which outputs signals corresponding to the existence or non-existence of toner in the hopper in response to the amount of the light received from the light-emitting element.