| 摘要 |
PURPOSE:To prevent dirt of the detecting surface of a detecting apparatus and to detect the concentration of a toner exactly over a long period of time, by providing a discharge port on a probe cover, and discharging a floating toner which has entered the side of an optical detecting apparatus. CONSTITUTION:A rotary probe 8 and a probe cover 11 are provided on the upper part of a magnet roll 2, an optical detecting apparatus 9 consisting of a light emission element 13 and a photodetecting element 12 is installed to the cover 11, and the concentration is detected by variation of reflected rays of a toner. Also, on the cover 11, a discharge port 13 for a floating toner is provided, and is connected to a chamber 14. According to this constitution, even if the floating toner enters the cover 11, it is discharged into the chamber 14 through the discharge port 13, therefore, dirt by a toner on the detecting surface is prvented, and the concentration of a toner is detected exactly over a long period of time. |
