| 摘要 |
PROBLEM TO BE SOLVED: To always accurately, easily and stably detect the existence of toner in a toner carrying path by means of an emptiness detecting sensor by providing the emptiness detecting sensor in a state where its detecting surface is exposed to the internal base of the toner carrying path. SOLUTION: The toner T fed from a toner cartridge 10 is temporarily stored in a reserve tank 2 and fed to a developing device by a required amount when it is required. The tank 2 is provided with the emptiness detecting sensor 5 at a bottom part corresponding to a position near to a center part from the toner introducing port of a toner storing and carrying path. The sensor 5 is a piezoelectric sensor which detects the existence of the toner T according to whether or not the toner T being carried comes in contact with the detecting surface 50 at a specified rate, and is attached in a state where the surface 50 is horizontally exposed to the internal base 20a of the carrying path. A spiral agitator 26 is set to rotate in a state where it approaches to the surface 50 to such an extent that it nearly comes in contact therewith. |
