| 摘要 |
PURPOSE:To eliminate the need to correct a detection error due to the secular change of a toner density sensor and reference toner density by detecting toner density and setting the reference toner density, and resetting a last developer current value and storing a developer current which is detected newly. CONSTITUTION:The developer current which is detected last time is compared with the developer current which is detected newly by a developer current detecting means 9 to decide whether or not a developer is new. A toner density detecting means 5 detects the toner density according to the comparison decision result of a developer current comparison decision means 19b and the value is set as the reference toner density. Further, the last developer current value stored in a developer current storage means 21 is reset and the developer current which is detected newly is stored. Therefore, when the developer is replaced with a new developer, the reference toner density is corrected automatically. Consequently, the error due to the secular change, etc., of the toner density sensor, manual misadjustment, etc., are eliminated. |
