As electrophotography has become established, the range of raw materials available has grown. This leads to the development of new colorants that are optimized for this application. For the toner manufacturer this is both a benefit and a problem. Full evaluation of new products involves dispersing the pigment (generally using an extruder) and then milling the dispersion with further ingredients to make a usable toner. This process is acceptable for a few samples of new products but few toner makers would be able to carry it out on every new colorant that comes onto the market. For the colorant maker, the problem is even greater since every new product to reach the market is the result of hundreds of research samples, all of which need to be tested. There is a need for a screening test that will allow a quick evaluation of the likely colouristic performance of new colorants in toner type systems. This paper introduces two possible techniques. One gives the possibility to screen large numbers of samples for colouristic performance, while the second allows a rapid screening of extruded dispersions without the need to formulate a full toner capable of acceptable printing.
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