| 摘要 |
PURPOSE:To automatically set the measured concentration of toner as the reference concentration of toner by providing a means for measuring the reference concentration of toner of a developing unit in a copying machine main body. CONSTITUTION:A fuse 24 in the developing unit 2 is connected to a use state detection circuit 16 in the copying machine main body. The use state detection circuit includes an FET 17 and a burning-off signal is outputted from a CPU 11 to the FET 17 when the developing unit is in a consumed state. Then, an excess current is applied to the fuse 24 to be disconnected. Therefore, based on whether or not the fuse 24 is connected, the consumed state of the developing unit 2 is discriminated. A dip switch (DIPSW) 21 showing control voltage (reference concentration of toner) is provided in the developing unit 2. It is switched in accordance with the developer inside at the time of inspecting products to control the concentration of toner of the developing unit. The control voltage read from a DIPSW 21 is stored in a RAM 13 in the copying machine main body. |
