Characteristics of Conductive Roller Transfer Using Constant Current Biasing

Abstract

Biased roller transfer is attracting attention because it does not generate ozone and because it has a greater operating range than corona transfer. Conventional roller transfer with constant voltage biasing has a drawback in that paper thickness affects the transfer ratio. We previously proposed constant current biasing as an alternative.
In this work, we examined the basic and useful characteristics of conductive roller transfer using constant current biasing, both theoretically and experimentally. Our investigation produced the following results. First, similar to the main transfer factor in constant voltage biasing, the transfer charge on paper determines the transfer characteristics, where the charge corresponds to the electric field between the paper and a layer of toner on the photoconductor. Paper thickness does not affect the transfer ratio if biasing is done with a constant current corresponding to an optimum transfer charge of 500μC/m². Second, the effect of paper width can almost be eliminated by using a transfer roller with a resistivity of over 10⁹Ωcm. Third, the optimum transfer pressure is in a range of 25 to 50gf/cm. Finally, ensuring that the speed difference between the transfer roller and photoconductor is no more than a few percent prevents the omission of characters during printing.