摘要 |
An apparatus which measures the usage of toner in a developer unit. A donor roll (74) receives toner material from a mixer (44). The mixer fluidizes the toner with the pressure from newly discharged toner moving the fluidized toner from one end of the developer unit to tile other end thereof. An electrical bias is applied between the donor roll and mixer. The current biasing the mixer is detected and a signal transmitted in response thereto corresponding to the usage of toner in the developer unit. This signal controls the discharge of toner into the developer unit. |