| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that toner ratio concentration is unstable when it is set so that when humidity is >=70%, compensation of the toner ratio concentration is to be executed and the humidity is 69% at one time, 70% the next instant and 69% the next and the compensation of the toner ratio concentration is sometimes carried out and sometimes is not carried out. SOLUTION: In this device, an ATC sensor 2 for detecting the toner ratio concentration of two component developer of a developing device 1, a humidity sensor 5, a compensating means to compensate the toner ratio concentration value of the two component developer in the developing device 1 according to detected humidity of the humidity sensor 5 and CPU3 with a control means for controlling the toner ratio concentration inside a developing device 1 to the toner ratio concentration value that is compensated by the above are provided. Then, when a device is installed or when the developer is exchanged, the toner ratio concentration detected by the ATC sensor 2 is stored, a storing circuit 3b storing the humidity detected by the humidity sensor 5 as a reference value for humidity is provided, and compensation for the toner ratio concentration is carried out by a compensating means by setting a compensation value of the toner ratio concentration, according to quantity of variation from the reference value for humidity stored to the storing device 3b from the detected humidity by the humidity sensor 5. |
