PURPOSE: To form an image having high image density without image fog by using a combination of a specified positive charge toner and a specified positive charge photoreceptor.
CONSTITUTION: A thin layer of a positive charge toner is brought into contact with a positive charge photoreceptor uniformly charged and exposed, so that the positive charge toner is deposited due to the difference of the potential on the area where the potential is decreased by exposure on the surface of the positive charge photoreceptor. In this contact developing method, a combination of a positive charge toner and a positive charge photoreceptor having a single layer of a positive charge org. photosensitive layer on the surface of a conductive base body is used. Into the positive charge toner, a resin having groups corresponding to quaternary ammonium salt introduced into the side chains is added as a charge controlling agent. Since the positive charge toner using the resin having charge controlling property does not match with the single layer of the positive charge org. layer formed on a conductive substrate concerning to electrification characteristics, the toner can be efficiently transferred from the thin layer on the surface of a developing sleeve to the exposed part on the surface of the photoreceptor, while no toner is transferred to the nonexposed part.
KURAMAE YOSHIHISA
NAGAI TAKASHI
TAKATSUNA TOORU
