A NEW ELECTROPHOTOGRAPHIC DEVELOPING SYSTEM WITH A SLEEVE FREE MAGNETROLLER

A new electrophotographic developing system was created to simplify th e developing unit. The new developing unit is simple and features a ma gnetic 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 ma gnetic 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 e ither toner concentration or electric resistivity of the carrier, but were affected by the size of the carrier. The best image quality was o btained by using a carrier 35 mu m in diameter. The new system demonst rated print image quality that was nearly as high as that produced by conventional developing units with a sleeve.