Xerox Corporation

Powerprint Technologies, Inc.

Powerpoint Technologies, Inc.

Arvind R Saklikar

Lorin K Hansen

William A Lloyd

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.

Method and apparatus for determining the quality of a colloidal

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. Based on the peak-to-peak value and the phase difference, the quality of the colloidal suspension is determined.

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.

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Sunnyvale, CA, United States of America

Arvind R Saklikar