| 摘要 |
PURPOSE:To accurately detect the presence or absence of developer in a process cartridge by disposing at least one of the light emitting and receiving parts of a developer detecting means so that it can move to a retreat position. CONSTITUTION:Supporting members 28 and 29, which involve the light emitting and receiving pats 27a and 27b, respectively, of a toner detecting means 27, can move at the time of the attachment of the process cartridge 10 to a device main body and its detachment therefrom. When the process cartridge 10 is attached to the device main body, the supporting members 28 and 29, which have the light emitting and receiving parts 27a and 27b, respectively, can adhere to the recessed bearing surfaces 19 and 19 of the process cartridge 10, and consequently the toner detecting means 27 can be accuratly positioned in the optical path 10b of the process cartridge 10. Thus, accuracy for detecting toner T in the developing unit 13 of the process cartridge 10 can be sufficiently increased without a complicated, expensive toner detecting means. |
