| 摘要 |
PURPOSE:To always make toner concentration accurate and constant by writing the reference toner concentration of developer in a nonvolatile memory, comparing the toner concentration at the time of forming an image with the reference toner concentration read out from the memory and replenishing the toner. CONSTITUTION:When initial setting is instructed from an operation input part 31, a voltage in accordance with the developing toner of the reference concentration measured by an inductance sensor 34 passes through an A/D converter 36 and written in the nonvolatile memory 37 according to the indication of a CPU 30. During development, the toner concentration gradually lowers. Now, a detection output from the sensor 34 is impressed on one terminal of a comparator 39. Meanwhile, the detected voltage of the sensor at the time of getting the reference toner concentration written in the memory 37 is impressed on the other terminal of the comparator 39. The comparator 39 outputs the voltage in accordance with the difference between both of them and a toner replenishment indication means 40 issues the indication whether or not the replenishment of the toner is performed to a toner replenishing means 35. Based on the instruction, the replenishment of the toner to the developer is performed. |
