Particle Size-Selective Transfer

Paper i proceeding, 1997

For every jumping powder development the competition between adhesion forces and the local electrical pull-off force determines whether development (transfer) is possible or not. With the general assumption that the toner charge is proportional to rn, n ≤ 2 for small particles, while for some developer systems it tends to become proportional to r for larger sizes, a theoretical model for this phenomenon was developed.

Our calculations predict the influence of magnetic adhesion, toner charge, nonuniform toner surface-charge density, choice of materials, and electrical field strength on a particle size-selective development. A strong indication of the relation between nonuniform toner surface-charge density and particle size-selective transfer is presented. Also an explanation of particle size-segregated toner layers is suggested.

Ideas on how to decrease the selectivity are suggested on the basis of our investigation.