Patent ID: 7840152

Claim:
A cleaning system for collecting a residual toner that remains on a surface of a latent image carrier after transferring, to a surface moving member, a toner image that is formed by uniformly charging the surface of the latent image carrier by a charging unit, by forming a latent image by a latent image forming unit on the surface of the latent image carrier, and by developing the latent image to a toner image by a developing unit, the cleaning system comprising: a temporarily-retaining unit that includes a magnetic field generating unit fixedly disposed inside a rotating member, the rotating member spaced apart from the latent image carrier and configured to carry a magnetic particle as a magnetic brush on a surface of the rotating member, the temporarily-retaining unit temporarily and mechanically retains the residual toner abutting on the latent image carrier while the residual toner travels from a transferring unit to the latent image forming unit; a bias applying unit including a first power supply and a second power supply, the bias applying unit selectively applies a retaining bias with the first power supply and applies an emission bias with the second power supply to the magnetic brush of the temporarily-retaining unit; and a controlling unit that at a predetermined timing controls to return the residual toner retained by the temporarily-retaining unit to the surface of the latent image carrier, wherein the rotating member is rotated at a faster velocity than the latent image carrier, and wherein the retaining bias has a potential equivalent to a potential of the surface of the latent image carrier after passing through the transferring unit, the emission bias has a same polarity as a polarity of the potential of the surface of the latent image carrier after passing through the transferring unit, and has an absolute value that is larger than an absolute value of the potential of the surface of the latent image carrier after passing through the transferring unit.