New patent application published for: DEVELOPING DEVICE AND IMAGE FORMING APPARATUS

Supposing that position P represents a position at which a ratio of a resultant force of a vertical magnetic force and a horizontal magnetic force of a developer separating part becomes maximum, and that position Q represents an intermediate position between positions Q1 and Q2, and that a distance of the magnetic force reversal region is α, and that a distance between positions Q1 and Q2 is β, and that a distance between positions P and Q is γ, and that γ has a positive value when position Q is on the upstream side of position P in the rotation direction, and that γ has a negative value when position Q is on the downstream side of position P in the rotation direction, then the following inequality (F1) is satisfied.α−(18.9×(γ/β).sup.2+20.8×(γ/β))>6 (F1)