| 摘要 |
PROBLEM TO BE SOLVED: To provide a process cartridge provided with a developer quantity detector being capable of sequentially detecting the quantity of toner in a toner container and easily predicting a life limit period and excellent in detecting accuracy. SOLUTION: A cylindrical tube 15 whose top and bottom ends are opened is arranged in the toner container 10a and a sound wave generator 16 and a receiver 17 are installed in the upper part of the cylindrical tube 15. A slit 15c is formed from the top end to the bottom end in the tube 15, so that the toner can easily enter. The surface position of the toner is lowered according to the consumption of the toner and this change is sequentially detected as the displacement of a sound wave. Moreover, a second developer quantity detector provided with an antenna is arranged in the vicinity of a developing roller, to detect the exhausting of the toner. |
