Discrete element modeling of the transient heat transfer and toner fusing process in the Xerographic printing of coated papers
In this study, a computer model based on discrete element method is employed to simulate the unsteady state heat transfer from the fuser roll to the toner and coating layer during the Xerography printing of coated papers. The model coating layers consisted of randomly arranged spherical pigment and latex particles with commercially relevant size distributions. Effects of coating characteristics, toner size, multiple toner layers, toner melting energy, toner thermal conductivity, coating layer thermal conductivity, and fuser roll temperature and pressure were investigated. Iso-thermal contours of fusing time were generated to demonstrate the relative importance of different fusing conditions and toner properties. Simulation results showed that temperature variation highly depended on the toner size, toner melting energy and the fuser roll temperature. Moreover, simultaneous coupling of the compressive stress and heat transfer indicated that the pressure exerted by the fuser roll did not significantly affect the rate of heat transfer.
FEM–DEM modeling of thermal conductivity of porous pigmented coatings
Abstract In this study, a coupled discrete element-finite element approach was developed to predict the effective thermal properties of model pigmented coating layers. Using this approach the influence of coating structure and pigment and binder characteristics was investigated. It was found that pigments with a broader particle size distribution (PSD) resulted in a higher effective thermal conductivity of the coating layer due to the denser coating structure formed by the pigments. Furthermore, the predicted effective thermal conductivities of the coating layers were found to increase with pigment morphology changing from spherical, to needle-like, and to platy. The effective thermal conductivity of the coating layer increased with the increase in the binder content up to the critical pigment volume concentration (CPVC), but declined when the binder content was higher than CPVC. Lastly, it was found that an empirical equation; k eff = A ( 1 - φ v ) 3 k p φ p k l φ l , where kp and kl are the thermal conductivities of pigment and latex, and φp, φl, and φv are the volume fractions of pigment, latex, and voids respectively, can be used to estimate the effective thermal conductivity of the coating layer in good agreement with the FEM–DEM simulation results.
Investigations of dielectric gratings using electrodynamic models based on volume integral equations
Eigenmodes of planar and cylindrical dielectric gratings (DGs) and electromagnetic wave scattering from multiplayer DGs are investigated. The DG characteristics are calculated using numerical-analytical solution of integral equations (IEs).