| 摘要 |
PROBLEM TO BE SOLVED: To break loose aggregates present in a developing device on the upstream side of a position where developer is delivered to developer storage units on a developing roller side, without giving excessive stress to the developer.SOLUTION: A developing device includes a first developer storage unit 53Y that supplies a developer G and a second developer storage unit 54Y that supplies the developer G to a developing roller 51Y side, and two openings 58 and 59 for the developer G to circulate between the first and second developer storage units 53Y and 54Y. The second developer storage unit 54Y includes a second conveying screw 56Y conveying the developer G, which includes a forward winding part 56Ya having pitches formed in a forward direction to a developer conveyance direction, a reverse winding part 56Yb having pitches formed in a reverse direction, and a gap q provided between both the winding parts to send out the developer G. First and second delivery openings 59a and 59b each deliver the developer G from the second developer storage unit 54Y to the first developer storage unit 53Y, and are arranged on the upstream side and the downstream side in the developer conveyance direction across the gap q. |
