Developing device, and image forming apparatus using the same

An image forming apparatus comprising:

• an image supporting body on which a latent image is to be formed based on given image information;
• a toner source;
• a developing unit for developing the latent image, which is formed on said image supporting body, into a visible image using a toner delivered from said toner source;
• a transferring unit for transferring the toner of the image, which is developed on said image supporting body, onto a medium;
• and
• a power source for applying to said developing unit a bias voltage for development;
• said developing unit including
• at least one stirring and conveying member of an electrically conductive material, extending between said toner source and the image supporting body, for conveying a toner from said toner source to the image supporting body longitudinally along a toner delivery path and stirring the toner being conveyed, said stirring and conveying member being electrically charged by a bias voltage to be applied during the developing and hence also serving to charge the toner with electricity during the stirring,
• at least one toner gathering port, disposed in said toner delivery path, for temporarily halting the toner there during the conveying,
• at least one auxiliary stirring member of an electrically conductive material, movable in said toner gathering port, for further stirring the toner staying in said gathering port, said auxiliary stirring member being electrically charged by said bias voltage and hence also serving to further charge the toner with electricity during the further stirring, and
• a stop, disposed at said toner gathering port, for preventing said auxiliary stirring member from moving off said toner gathering port and for allowing the toner to pass through said toner gathering port.