| 摘要 |
PURPOSE:To decrease the number of connections between a main body and an image forming unit and to reduce the cost by detecting the toner density and whether or not the image forming unit is loaded from the output of signal of sensitivity adjusting signal of a toner density sensor. CONSTITUTION:The sensitivity adjusting voltage Va is adjusted so that when developer with toner/ carrier density of 5% is fed, outputted voltage Vo from the toner density sensor 13 becomes 2V. Further, when the image forming unit 40 is not mounted on the main body, the adjusting voltage is made Va2. Then the data related to the adjusted voltage Va1 is stored in writable and erasable ROM. Therefore, when the developer with the density of 8% is fed the voltage Va which makes the outputting voltage 2V from the sensor 13 is inputted and sensitivity adjustment is carried out automatically. Further, whether the unit 40 is mounted or not is detected by whether the outputting voltage when the adjusting voltage is made Va2 is 0.5V or less. Thus, the connection between the main body and the image forming unit can be decreased and the cost is reduced. |
