| 摘要 |
PURPOSE:To uniform the toner concentration in the width direction and prevent the copying density from being uneven. CONSTITUTION:A toner feed tube 19 with plural toner discharging ports 20 is attached to the width direction of a developing device 2. The other end of the feed tube 19 is connected to a toner hopper 22, the opening of nozzle 24 is connected to a pipe 21 and a projector 26 and a light receiver 27 are set up so as to oppose against a transparent window 25. When the toner concentration is diluted as the result of repeat of developing and the carrier concentration is increased, the quantity of light reflected by the projector 26 is increased and, if the quantity of reflected light exceeds a fixed value, a feed source 23 of pressured air starts by the output signal from the light receiver 27 and toner is fed by the back pressure of blowing from the nozzle 24. Thus, new toner is replenished uniformly to the width direction, preventing the copying density from being uneven. |
