A multiple process optimization strategy for manufacturing environmentally friendly printing toners

On the basis of response surface methodology (RSM), we obtained design criteria at which printing toners with acceptable environmental and engineering characteristics are produced. The toner is a fine powder mainly composed of a resin and a coloring agent, which has been widely used in digital printing. The optimization strategy has been testified to produce printing toners with appropriate physical (particle size (PS) and PS distribution (PSD)) and color (L∗, a∗, b∗) properties through emulsion aggregation (EA) route. The EA is inherently a unique, environmentally friendly process that gives the provider the benefits of an accurate and efficient printing. The influence of heating rate (R), mixing time (T), and mixing rate (S) on PS, PSD, and (L∗, a∗, b∗) has been studied, where a number of approximation functions including linear, linear with interaction, quadratic and cubic models were served to assess whether or not the response variables are governed by the aforementioned parameters. In addition, toners manufactured based upon RSM were characterized by scanning electron microscopy, colorimetry, and differential scanning calorimetry techniques. The results proved that the models used are hardly adequate for assessing the PS and L∗ responses. Moreover, PSD and a∗ were not governed by the chosen factors, as a whole. On the other hand, R and S variables have meaningful impact on b∗ and a quadratic model is consistent with the experimental data. The cubic model yielded the best coefficient of determination, where the desired toner was suggested to be produced at condition: R = 1200 rpm min, T = 90 min and S = 30 min.