Thermomechanical property of toner in electrophotography

The study is devoted to a comprehensive study of thermomechanical and physicochemical properties of toners in electrophotography. Konica Minolta BizHub C350 (CMYK) toner was selected for the study to optimize the performance of electrophotographic printing in production. The work emphasizes the critical influence of rheological variables of the melt on the final quality and efficiency of the printer, which requires taking these variables into account when setting up the process. For a comprehensive characterization of toners, a comprehensive set of methods was used: thermomechanical analysis: determination of thermal stability (TGA), glass transition temperature and melting point (DSK); rheological studies: study of the thermorheological evolution of the melt at the thermal bonding stage; physical and optical properties: assessment of particle size (laser analyzer), morphology (optical microscope) and color (spectrophotometer). It is proven that with increasing temperature, toner particles undergo initial surface thermal bonding (adhesion). It was found that the melting point of different colors is reached in a specific order that correlates with the standard four-color printing sequence (CMYK), highlighting the critical importance of thermorheological variables for multicolor printing. It was shown that the thermomechanical properties of the toner have a direct impact on the printer performance, and the change in melt viscosity is a key parameter that must be considered to improve the quality and speed of printing.

However, the effect of aging and the time frame of fixation need to be further investigated in future studies. This is important because the charging ability of printing toners deteriorates upon tribological charging. The results of the study showed that the toner particle size is about 10 μm, which provides a printing resolution of about 600 dpi. It was found that the toner particles have an irregular shape due to their manufacturing by grinding. Finally, the toner demonstrated suitable thermal properties (Tg ≈ 60 °C) for printing purposes and showed only one major decomposition step at 400 °C.

Keywords: toner, electrophotography, DSC, TGA, rheology, glass transition temperature, particle size, thermosetting.

doi: 10.32403/0554-4866-2025-2-90-72-82