| 摘要 |
PURPOSE:To detect toner density in a stable state invariably, by oscillating the hopper of a toner density detector provided with a piezoelectric oscillating body. CONSTITUTION:To the external surface of the hopper 8 of a toner density detector 7, a piezoelectric oscillating body 12 is fitted by a bonding method, etc. This oscillating body 12 has an electrode 12a for applying a driving voltage, and an amplifying circuit 13 and an oscillating circuit 14 are connected to the electrode 12a to drive the oscillating body 12 at the oscillation frequency of the oscillating circuit 14, thereby oscillating the hopper 8. Further, a scraping plate 15 for scraping a developer after development off from a developing roll 3 is provided. |
