| 摘要 |
PURPOSE:To obviate clogging even if a high density developer is used by oscillating forcibly a funnel-shaped hopper provided with an orifice by mans of a piezoelectric element on a discharging pipe wound with a coil. CONSTITUTION:A developer scraped from a developing sleeve glides partly down on a scraper and falls from an upper hopper 6 into an inside hopper 10 and is successively discharged through an orifice 11. When a toner density exceeds 4.0%, a toner sticks on the inside wall surface of the hopper 10 and forms a toner bridge in the orifice part, but an AC voltage is impressed at all times on a piezoelectric element 12 supporting the hopper 10 to keep the hopper 10 oscillated and therefore the sticking of the toner in the hopper 10 is obviated. |
