Installation and removal structure of a developing unit and a toner cartridge in an image forming apparatus

An image forming apparatus comprising:

• an image carrier on which a latent image is formed;
• a developing unit having means for supplying toner to the image carrier for developing the latent image when the developing unit is installed in a body of the image forming apparatus, the developing unit having an opening through which toner from a toner cartridge can be introduced thereinto;
• a toner cartridge mountable on said developing unit and covering said opening;
• and
• means on at least one of said developing unit and said apparatus body for prohibiting mounting or removal of said toner cartridge on said developing unit only when said developing unit is installed in the image forming apparatus body.

An image forming apparatus comprising:

• an image carrier on which a latent image is formed;
• a developing unit having means for supplying toner to the image carrier for developing the latent image when the developing unit is installed in a body of the image forming apparatus, the developing unit having an opening through which toner from a toner cartridge can be introduced thereinto;
• a toner cartridge mountable on said developing unit and covering said opening;
• and
• guide means formed on both said developing unit and said toner cartridge for guiding said developing unit and toner cartridge for installation in the image forming apparatus body only when said toner cartridge is mounted on said developing unit.

An image forming apparatus comprising:

• an image carrier on which a latent image is formed;
• a developing unit having means for supplying toner to the image carrier for developing the latent image when the developing unit is installed in a body of the image forming apparatus, the developing unit having an opening through which toner from a toner cartridge can be introduced thereinto;
• a toner cartridge mountable on said developing unit and covering said opening;
• and
• means on at least one of said developing unit and said toner cartridge for permitting removal of said toner cartridge from said developing unit only when said developing unit is installed in the image forming apparatus body.

An image forming apparatus comprising:

• an image carrier on which a latent image is formed;
• a developing unit having means for supplying toner to the image carrier for developing the latent image when the developing unit is installed in a body of the image forming apparatus, the developing unit having an opening through which toner from a toner cartridge can be introduced thereinto;
• a toner cartridge mountable on said developing unit and covering said opening;
• and
• means on at least one of said developing unit, said toner cartridge and the image forming apparatus body for prohibiting the removal of said developing unit from the image forming apparatus body when said toner cartridge is not mounted to said developing unit.