Particle Swarm Optimization for Cluster-Based Classification of Breast Cancer Data

The present invention provides a developing device for conducting image development with the use of a magnetic developer containing magnetic powder in a proportion not less than 20 wt. % and having a mean particle size not less than 5 microns and with a magnetic field of which flux density is not in excess of 950 gauss at the surface of the developer supporting member. Also the developing device is provided with developer leak preventing members, a developer recovering magnetic pole at an angular position theta 1 (<45 DEG ) downstream of the initial contact position of the preventing members with the developer supporting member and another magnetic pole at angular position theta 2 (< theta 1) upstream of the initial contact position.