| 摘要 |
PURPOSE:To obtain a stable and fine image by measuring the reflection concentration of the toner image of a standard display plate plural times whenever developer is replaced with fresh one and controlling the replenishment of toner. CONSTITUTION:Whenever the developer G is replaced with fresh one, a reference concentration setting mode is selected and the copying device repeats copying action plural times by the control of a control part 4. The mean value of reflection concentration measured plural times is calculated in the control part 4 and the calculated mean concentration value or a concentration value which is set lower by a fixed value is set in the storing part of the control part 4 as reference concentration of the toner image of the standard plate. After this, when copying is carried out, the reflection density of the toner image 42 of the standard plate which is developed by a standard developing bias is measured and compared with the reference concentration. When the density of the toner image of the standard plate is lower than the reference concentration, a toner replenishing roller 23 rotates and is controlled to replenish toner T. When its concentration is equal to or more than the reference concentration, the toner T is not replenished. Thus, the developer G is maintained at fixed toner concentration. |
