| 摘要 |
PROBLEM TO BE SOLVED: To provide the detector capable of being arranged in a comparatively free layout without providing any detecting structural body inside a developer container and without applying any load on the developer, and being used for plural kinds of developer containers different in capacity. SOLUTION: A remaining amount detection speaker 101 and a remaining amount detection microphone 102 are installed so as to be in contact with the upper part of the developer container 10 of the process cartridge 5, and a sound wave is emitted from the speaker 101 toward the developer container 10 and the acoustic wave is detected by the microphone 102. A 1st set value SL is set based on the effect that the wave length T of the acoustic wave changes correspond to the change in the space capacity of the developer container 10, that is, the variation of the remaining amount of toner. As for the set value SL, the 1st and 2nd set values SL and SL2 are set so that two large and small process cartridges different in the capacity of the developer container can be used. |
