Mechanism of Toner Scattering for Two-components development Systems

Abstract

Mechanisms of toner scattering from a developer unit for the two-components developer consisting of toner and insulative carrier have been examined by varying the covering ratio(θ)of a carrier surface with toners, the toner surface-area median size(d₅₀), and the carrier-area median size(D₅₀). It has been found that the toner-weight scattered down on the horizontal unit area in front of the developer unit, normalized by n particles of toners which were randomly distributed on the surface of one carrier, charged by triboelectrification, and adhered to the carrier (Wt/n), increases exponentially with increasing the covering ratio (θ), or surface-area ratio of n toners to a carier (ns_t/s_c), independent of the toner size and the carrier size. This exponential increase of the toner scattering, (W_t/n), is accompanied with a decrease of the product of toner surface-charge density (q/s_t) and contact electrostatic field (E_k) between the toner and the carrier, namely, with a decrease of Coulomb's force per unit area (qE_k/s_t) at the contact part of the toner and the carrier.