IMAGE FORMING APPARATUS AND IMAGE FORMING METHOD

PROBLEM TO BE SOLVED: To provide an image forming apparatus and method for suppressing wasteful toner consumption and being compatible with small-diameter toner. SOLUTION: A developing roller 7a carries contact toner that is directly in contact with the developing roller 7a and non-contact toner that is not in contact with the developing roller 7a. Since the non-contact toner has a very small amount of charge, it is weakly returned to the developing roller side, and adheres to a non-exposed portion of a photoreceptor 2. By applying transfer bias Vt1 having a polarity (positive polarity) opposite to a regularly charged polarity (negative polarity) of the toner to an intermediate transfer belt 8a, discharge is generated between the non-exposed portion of the photoreceptor 2 and the intermediate transfer belt 8a at a front-side position TP0 of a transfer position TP. The polarity of negatively charged particles adsorbed to the non-exposed portion is inverted. By applying cleaning bias Vbr having the positive polarity to a brush roller 4a, only the negatively charged particles are sucked and removed from a surface of the photoreceptor 2 while allowing the positively charged particles to remain thereon. An image forming process proceeds in a state where a nearly constant amount of the positively charged particles always adhere to the surface of the photoreceptor 2. COPYRIGHT: (C)2010,JPO&INPIT