A new electrophotographic developing system with a sleeve free magnet roller

摘要

A new electrophotographic developing system was created to simplify the developing unit. The new developing unit is simple and features a magnetic roller without a sleeve. The sleeveless magnet roller was made of a sintered ferrite magnet 20 mm in diameter and magnetized with 32 poles. This developing system can be applied to both mono-component magnetic toners and conventional dual-component developers. Factors and developing conditions that influence image quality were examined using a variety of developers where both the toner and carriers were magnet. Images printed with the new developing unit were not influenced by either toner concentration or electric resistivity of the carrier, but were affected by the size of the carrier. The best image quality was obtained by using a carrier 35 mu m in diameter. The new system demonstrated print image quality that was nearly as high as that produced by conventional developing units with a sleeve.