Toner is a critical material in printing and copying processes. Compared to the conventional pulverized toner, polymerized emulsion aggregation (EA) toner provides more precise control over the shape and surface roughness of particles. Due to its roundness and low surface roughness, the near-spherical EA toner appears to adhere more strongly to flat substrates, which is desirable for efficient toner transfer and development. However, in the cleaning and transport processes, due to enhanced adhesion, it is difficult to remove the residual EA toner from surfaces of the photoreceptor and transport belt. To reduce the adhesion of the EA toner in a controllable manner, the surfaces of the toner particles are coated with silica nanoparticles with a diameter range of 15–32 nm. In the current study, a technique based on the rolling resistance moment of the particle-substrate adhesion bond is utilized for quantifying the effect of nanoparticle surface coating on the adhesion of individual toner particles. With the aid of a custom-made nanomanipulation system, an increasing lateral pushing force was applied to an individual toner particle adhered to a silicon substrate while the pre-rolling and rolling motions of the particle in response to the lateral pushing force were recorded. The work of adhesion between the toner particle and silicon substrate was extracted from the corresponding lateral force-particle displacement curve. The technique was used to characterize the adhesion properties of both uncoated (bare) and nanoparticle-coated model toner particles with a specified surface area coverage of 50%. It is found that the work of adhesion values between the surface-coated experimental toner particles and the silicon substrate are almost an order of magnitude lower than those for the bare ones.
Huan Zhang, Weiqiang Ding, Cetin Cetinkaya, "Effects of Nanoparticle Coverage on the Adhesion Properties of Emulsion Aggregation Toner Particles" in Journal of Imaging Science and Technology, 2010, pp 20501-1 - 20501-7, https://doi.org/10.2352/J.ImagingSci.Technol.2010.54.2.020501