| 摘要 |
PURPOSE:To set a toner density reference level in a short period at the time of replenishing a toner, by extracting toner concentration detecting levels of three points or more while the toner concentration detecting level is stabilized, and deriving the toner concentration detecting level in a stable area, by an arithmetic operation. CONSTITUTION:A two-component developer whose toner concentration is known is thrown into a developing tank and stirring is started, and thereafter, from toner detecting levels of at least three points or more which have been extracted in a short period, a toner concentration detecting level of the developer which is stabilized by stirring is derived by an arithmetic operation. Accordingly, the toner concentration detecting level in a stable area, which has been derived by this arithmetic operation is set as a toner concentration reference level at the time of replenishing a toner. Therefore, when concentration of the toner has dropped by a developing process, a prescribed toner concentration can always be kept by replenishing the toner so that the toner concentration detecting level becomes this toner concentration reference level. |
