| 摘要 |
A device for sensing the amount of residual toner in a developing apparatus which uses an electrophotographic developing process. The device incorporates an agitator installed in a housing of the developing apparatus, a support formed at one end of the agitator, a plate rotatably coupled with the support and having a magnet attached at one end thereof, a torsion spring whose one end is fixed on the support and the other end is fixed on the plate, and a reed switch installed at the bottom portion of the housing. The reed switch is turned off when the plate is deflected upward around a hinge pin against the a resistant force of the toner, and the reed switch is turned on when the plate does not encounter a sufficient resistant force from the toner. When the plate is extended and stretched in parallel with the support, and the magnet and the reed switch correspond to each other, the reed switch is activated, indicating a low amount of toner in the housing.
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