To stabilize replenishment of toner to a development machine by preventing excessive replenishment of the toner to the development machine and reverse flow of the toner to the toner replenishment container even in the course of the revolution of a rotary development apparatus.
A developer replenishment device 26 having a toner conveyance pipe 6 and a toner conveyance screw 3 for replenishing developer to the development machine, wherein a magnetic shutter 3a which opens or closes the toner discharge port 6a of the toner conveyance pipe 6 is disposed on the toner conveyance screw 3 near the toner discharge port, magnets 7 which are opposite to the magnetic shutter 3a to thereby form magnetic seals 8 between the magnetic shutter 3a and the magnets 7 themselves are disposed at a toner conveyance pipe opposite position which is opposite to the magnetic shutter 3a when the magnetic shutter 3a closes the toner discharge port, and the toner conveyance screw 3 is stopped at a position where the magnetic shutter 3a closes the toner discharge port 6a when the rotation of the toner conveyance screw 3 stops, the position opposite to the magnets 7.
Hiroyuki Nakagawa
Kosuke Tobita