ELECTROPHOTOGRAPHIC DEVELOPER AND IMAGE FORMING METHOD

摘要

PURPOSE:To obviate the generation of a disturbance in the toner image by 1st development at the time of single process multicolor development by providing the positively charged developer having the excellent environmental stability of electrification and electrification maintenance characteristic and the image forming method using this developer. CONSTITUTION:The electrophotographic positively chargeable developer consists of a toner a quaternary ammonium salt compd. or hydrophobic silica particles treated with a polymer having a quaternary ammonium salt structure as a functional group as an external additive and a magnetic carrier coated with a coating material contg. a negatively chargeable resin and methyl phenyl silicone resin. This positively chargeable developer is suitable for use in the 1st development in the method for forming the multicolor images by successively superposing the latent images of plural systems formed on a latent image carrier and developing these images with the toners of different colors and simultaneously transferring the images onto a transfer medium 9.