| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming device capable of controlling toner concentration to be constant without providing a special sensor even when the permeability of developer is changed by environment. SOLUTION: This image forming device is equipped with a developing device 5 using two-component developer, and the toner concentration of the developer in the device 5 is controlled only by a magnetic sensor, then output from the magnetic sensor for initial developer is set as a reference value for controlling the toner concentration at the time of charging new developer in the device 5. It is assumed that the toner concentration control reference value at the time of charging the new developer in the device 5 is VT0, and the output value from the magnetic sensor at the time of stirring for a fixed time when a main body power source is turned on and before starting forming the image is VT2. At such a time, in the case the VT2 is different, from the VT0, a toner concentration control value at the time of starting forming the image is changed to the VT2, so that the toner concentration value is controlled to be the fixed value regardless of environment. |
