The Fusing Enhancement of Background

Background is a printing phenomena unique to xerography. Background is the result of the random deposition of particles in the nonimage area. These particles are not objectionable until they are fused onto the copy. The fusing step caused the particles to spread out making them detectable and, in some cases, objectionable. This analysis deals with the spreading out of toner particles in the background. A model is developed which predicts that the particles are flattened to a degree depending upon their initial size, the size of the paper asperities, the toner viscosity, the roll fusing nip pressure, and residence, time in nip. A dimensionless parameter x is used to relate the enhancement to the nip geometry. Equations are also presented that allow the user to translate size distribution data from one fuser to another. The model for enhancement is compared to experimental data, and it is shown that the average error in predicting the fused particle size distribution is within 15 percent.