Abstract: A method and apparatus for determining the quality of a colloidal suspension. According to the method of the present invention, an oscillating input electrical signal is applied simultaneously to a sample of the colloidal suspension to be tested and to a reference resistor. The reference resistor has a predetermined impedance value that is substantially identical to the colloidal suspension. The input signal causes charge particles and molecules within both substances to move, thereby, giving rise to electrical currents. Thus, a test current is extracted from the colloidal suspension and a reference current is extracted from the reference resistor. Thereafter, a differential output current is derived by subtracting the reference current from the test current. The average value of the differential output current and the peak value of the test current are measured. Based on the peak value of the test current and the average value of the differential output, the quality of the colloidal suspension is determined.

Abstract: A method and apparatus for determining the quality of a colloidal suspension. According to the method of the present invention, an oscillating input electrical signal is applied simultaneously to a sample of the colloidal suspension to be tested and to a reference solution. The reference solution is substantially identical to the colloidal suspension except that the colloidal particles have been removed. The input signal causes charge particles and molecules within both substances to move, thereby, giving rise to electrical currents. Thus, a test current is extracted from the colloidal suspension and a reference current is extracted from the reference solution. Thereafter, a differential output current is derived by substracting the reference current from the test current. The peak-to-peak magnitude of the differential output current is measured, and the phase of the output current is compared to the phase of the input signal to determine the difference in phase between the two signals.

Abstract: Flaring phenomenon in electrographic recording can be substantially reduce, if not eliminated, forming uniform latent image spots by providing a flaring suppressor agent in or on the surface of the dielectric charge retentive layer of the electrographic recording medium. The improvement comprises incorporating a flaring suppressor agent in the composition of the dielectric charge retentive layer of the electrographic recording medium or coating a flaring suppressor agent on the surface of the dielectric charge retentive layer of the electrographic recording medium to enhance the charge retentive properties of the layer and quench lateral electrical discharge breakdown during recording use thereof. A suitable flaring suppressor agent comprise fluoro carbons or fluoro sulfurs or organo metallic salts or soaps. Specific examples of agents are polyvinyl fluoride, sulfur hexafluoride or zinc stearate.

Abstract: The apparatus for applying a stripe of colorant to a polymeric surface includes a spring biased, rotatably mounted circular magnet having a predetermined width. Non-magnetic walls extend radially outwardly from the magnet and are biased against the polymeric material. A retainer for holding a mixture of a ferro-magnetic carrier and a non-magnetic colorant is located within the magnetic field of the circular magnet. A rotatably supported roller on the side of the polymeric surface opposite the magnet supports the polymeric surface as it moves.The process of applying a stripe of polymeric colorant to an embossed electrically uncharged polymeric surface including rotating a wheel-shaped magnet, attracting a mixture of ferro-magnetic material acting as a carrier for a polymeric colorant to the magnet and pressing the magnet with the mixture against the polymeric surface.