Three Dimensional Simulation of Transfer Process

Abstract

A three-dimensional calculation of a first transfer subsystem in an electrophotograpy is carried out and toner scatterings on a transfer belt are simulated. This simulation consists of an electric field calculation and a toner movement calculation. In order to estimate electric field precisely, Boundary Fitted Coordinate (BFC) is used for the finite deference method to consider shapes of a photoconductor drum and rollers. To calculate force on a toner in detail, force from electric field, discharge phenomenon, resistivity of materials and toner adhesion force are considered. A toner detaches from the photoconductor and begins to move downward to the belt when the force on the toner is greater than adhesion force between the toner and the photoconductor. Toner movement is calculated according to Newton's law of motion and the dot image on the belt is simulated. Toner scatterings, which result in a loss of sharpness and resolution, are recognized around the peripheral of the dot. The simulation shows that toner scattering formation arises from the toner jumping across the transfer gap before the photoconductor contacts the belt. The effects of transfer parameters on toner scatterings are investigated with the simulation. To suppress toner scattering, the position of the roller, transfer bias, and the resistivity of the belt should be optimized to create an appropriate electric field distribution and to realize that the toner transfer happens in a small gap or in a contact nip with the photoconductor and the belt.