Control means for a transfer charger in an image forming apparatus

摘要

An image forming apparatus wherein a toner image formed on a photosensitive member or a toner image once transferred therefrom to a transfer belt is transferred onto a copy sheet by a transfer charger, and the output of the transfer charger is controlled so as to apply a specified amount of charge to the copy sheet for fine image transfer. Specifically, an electric current flowing in the copy sheet is estimated based on an electric current flowing in the transfer belt when no sheets are on the belt, and the output of the transfer charger or alternatively a bias voltage impressed on a roller which supports the transfer belt is controlled so as to cause a specified value of electric current to flow in the transfer belt.