The advantages and disadvantages of chemically produced toners (CPT) vs. conventionally produced toners by grinding and classifying are top of discussion. All OEM's of CPT contend that their toners are characterized by smaller particle size, tighter particle size distributions
and higher consistence in particle shape. The ideal spherical or at least “potato” toner particle shape effects a higher capability of rendering better image quality. Goal of our investigations was to improve the circularity of conventionally produced toner particles and to
correlate the generated particle shape as well as the resulting imaging quality parameters. Test material was an adjusted purchasable CPT that was prepared in the conventional way. In the first part of this presentation results of systematic investigations according to rounding conventionally
produced toner particles will be presented. Extensive tests on a conventional intensive mixer Cyclomix by HOSOKAWA Micron B.V., Doetinchem/The Netherlands, and the new high-intensive mixer NOBILTA by HOSOKAWA Alpine Aktiengesellschaft, Augsburg/Germany, were conducted to evaluate optimal processing
conditions. The second part deals with the consequences of rounding on printing quality parameters like solid black density, ghosting, fixing and level of grey, the correlation of particle circularity and printing quality parameters as well as the comparison of mechanically rounded toner
particles to chemically produced toner particles. First results show that it is possible to generate the desired potato shape by intensive mixing on Cyclomix as well as on NOBILTA, both kinds of intensive solid mixer. The printing tests gave fully satisfying results in almost all criteria
and are comparable to CPTs. In order to utilize all benefits of rounded toner quality the entire toner production process must be taken in consideration, i.e. from formulation to blending. Further investigations including trials on the Fluidics Coating Device will be conducted to optimize
the rounding step and to evaluate the optimal mechanically rounding process.
Document Type: Research Article
Publication date: January 1, 2010
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