Abstract: A method for making conductive toner particles includes (A) heat treating in fluidized bed processing equipment a mixture of non-conductive toner particles containing a thermoplastic resin and a colorant, and an effective amount of conductive powder blended with and coated on surfaces of the non-conductive toner particles, wherein the heat treatment is carried out at a temperature at or above the glass transition temperature of the resin for a period of time at least sufficient to fuse the conductive powder onto the surfaces of the non-conductive toner particles, and then (B) cooling the heated conductive toner particles to a temperature below the glass transition temperature of the resin. The final toner particles have a conductivity of at least about 10.sup.-8 ohm.sup.-1 -cm.sup.-1 and preferably from about 10.sup.-4 to about 10.sup.-8 ohm.sup.-1 -cm.sup.-1.

Abstract: A system is disclosed that monitors the concentration of material in a fluid carrier which includes means for circulating the fluid carrier within a substantially closed loop system and means for measuring the concentration of material carried in the fluid. The measuring means includes means to detect rapid changes in transmissivity of the fluid carrier, which are indicative of the presence of entrained air bubbles in the fluid carrier, so that measurements of material concentrate under such conditions may be ignored or rejected. Further, to ensure that an accurate measurement of concentrated material depletion is being observed, more than one consecutive measurement is made and validated before concentrate is finally added to the fluid carrier in the system. In the preferred embodiment, the determination of whether air bubbles may be entrained in the fluid carrier is accomplished by determining a disparity between two consecutively measured samples to have been greater than a predetermined value.

Abstract: A multi-layered package for a magnetic domain device including self-contained in-plane switching magnetic field coils surrounding one or more magnetic domain device chips and a permanent magnet surrounding the switching magnetic field coils. The switching coils are formed by two printed circuit layers, each layer comprising an insulating substrate having striped conductive patterns orthogonally oriented relative to each other on the opposite surfaces of the insulating layer. The ends of the striped conductors on one printed circuit layer are connected to the ends of the corresponding striped pattern on the other printed circuit layer so as to form one of the switching coils. The ends of the other pair of striped conductive patterns are similarly connected to form the second switching coil. The magnetic domain device chips are placed inside the formed switching coils which, in turn, are surrounded by the permanent magnet.